You can probably think of other reasons, but I boil them down to two main categories: supply and demand. I'll take them in reverse order; i.e., first I'll look at the demand for more information/clarity, then I'll look at the supply of more information/clarity.
1. Urgency (demand). Like many Latter-day Saints, I feel a sense of urgency about this issue. You probably do too. We're all concerned about the ongoing confusion that the two-Cumorahs theory sows among the Saints and among investigators. I guestimate that about 90% of active LDS accept pretty much whatever they're told about the topic; i.e., their primary, Sunday School, seminary, Institute or BYU teacher (or parents) told them the Book of Mormon took place in Central America, using Church-approved artwork, so they accept it and move on without questioning.
Around 10% question what they're told and don't believe it for any of a number of reasons.
(BTW, I think Letter VII would reverse these numbers, if it were widely known. The number of people who would question the Mesoamerican theory after reading Letter VII in the context of teachings of the modern prophets and apostles would approach 90%, which explains why the scholars and educators have suppressed Letter VII, as I've shown in my video series.)
Another reason for urgency is the societal trend toward empiricism and away from faith. In the early days of the Church, missionaries used the Bible to prove the Book of Mormon because most people believed the Bible. Now, hardly anyone believes the Bible, so that approach doesn't work. Instead, it will be the unique divine authenticity of the Book of Mormon that proves the Bible. That's the topic of a book I'm working on, but I can't publish until we LDS get our act together and agree on the historicity and geography of the Book of Mormon.
Yet another reason is the Internet, as the following scenarios illustrate. These are typical of what happens thousands of times on a regular basis.
Imagine you're not LDS and missionaries come to your door. They tell you about the Book of Mormon. You've heard about it, but don't know much about it. They leave you with the missionary edition. You thumb through the illustrations. You see Alma baptizing in a mountainous, jungle wilderness. You see Samuel preaching from the top of an enormous Mayan stone wall. You see Christ appearing to Mayans among Mayan ruins (with Chichen Itza in the background). You don't know much about ancient history, but you did learn about Mayans, and maybe you've visited Cancun, so you get the picture. You actually visited Chichen Itza and you're curious about the connection with those ruins and the Book of Mormon.
Then you start reading. 1 Nephi starts out interesting, with the family fleeing Jerusalem, but then it gets into a weird apocalyptic vision. Next are long quotation from Isaiah. You wonder where the Mayans are.
You get on the Internet and in 30 seconds, you find out the Mormons actually have no idea where the Book of Mormon events took place. Web pages explain that the first Mormon prophet, Joseph Smith, said the Hill Cumorah was in New York, but the LDS scholars now say he was confused and didn't know what he was talking about. You discover that, despite the illustrations in the book the missionaries gave you, the text actually says nothing about Mayans, pyramids, or jungles. The web pages claim the Mormons can't even agree among themselves about the geography because the work is fiction written by Joseph Smith and others.
The missionaries call to confirm the next appointment and, because they're such nice, idealistic kids and you don't want to hurt their feelings, you tell them you don't have time to see them right now. They call a few more times, and you finally tell them you're not interested.
Imagine you're a missionary, and you regularly run into former Mormons and well-prepared Christians who tell you the Book of Mormon is fiction. They tell you you're wasting your time, and they refer you to the Internet to see for yourself. You don't take their advice at first, but after months of this, you and your companion decide you need to be prepared for the objections you keep encountering.
You look up FairMormon.
You find out that the anti-Mormon literature is correct.
FairMormon and the LDS scholars cited there do actually say Joseph Smith, Oliver Cowdery, Joseph Fielding Smith, etc. were speculating, didn't know what they were talking about, and were wrong. You remember what your seminary, Institute, and BYU teachers told you about Mesoamerica and now you realize for the first time that theory contradicts what Joseph, Oliver and the others said.
You read Letter VII and you're shocked you were never told about this before. You always thought it was far-fetched to believe Moroni hauled the heavy plates and other artifacts to New York from southern Mexico, but you accepted it on faith. Letter VII makes a lot more sense, but it contradicts everything your Church teachers have told you. You start to wonder: if they were wrong about the Hill Cumorah, what else were they wrong about? Soon you question everything your teachers told you. You still don't have answers for the antagonistic people you meet every day; in fact, you have more questions than answers.
You tell your companions about Letter VII. Some agree it's a problem, but most think you're an apostate for even reading something like that. Your Mission President gets angry when you ask about it and doesn't answer your questions. He says your teachers were right, and whatever this Letter VII is, it's not approved by the Church.
You return home and make excuses for missing Church meetings and before you know it, you're no longer active in the Church.
These are just two of any number of similar scenarios that happen all the time, all around the world.
Hence, the sense of urgency. It's time for us to get our act together and stop promoting theories of geography that contradict Joseph and Oliver and the other prophets and apostles.
2. More evidence (supply). The Joseph Smith Papers project has brought many things to light that were previously unknown. I've been following the geography debates for over 40 years. Not once did anyone tell me Joseph Smith had his scribes copy Letter VII into his own history as part of his story. (Not that anyone mentioned Letter VII at all--it has been suppressed from every Church history resource I had access to, not to mention FARMS, FairMormon, and the rest. It was available in the Times and Seasons, a set of which I purchased when I was in my 20s, but I didn't realize that.)
Thanks to the Joseph Smith Papers, we can trace all the Church history I described in The Lost City of Zarahemla, Brought to Light, and The Editors: Joseph, William, and Don Carlos Smith. I couldn't have written those books without the Joseph Smith Papers as a resource.
The newly accessible historical data has helped us distinguish between what Joseph actually taught and what was merely attributed to him. That, in turn, has eliminated much of the confusion about the issue.
[See my comments on sowing confusion here.]
We also have more evidence than ever before in terms of archaeology, anthropology, geography, and geology. More is coming out all the time.
In a real sense, faith precedes the miracle here. IMO, as more and more LDS refocus on what Joseph, Oliver (and other latter-day prophets and apostles) have said, instead of relying on the scholars and educators who reject them, even more evidence will come forward.
Understanding the Mesomania issue helps with this process, as well. We don't blame anyone for perpetuating the Mesoamerican and other non-NewYork-Cumorah theories. We understand the intellectual history and the psychology involved. Nothing about this is personal.
But we seek clarity and all the new evidence explains things pretty well.
- Yes, Oliver Cowdery did unequivocally state in Letter VII that the Hill Cumorah (Mormon 6:6) was in New York.
- Yes, Joseph did assist in writing these historical letters, had them copied into his own history, and approved their republication.
- Yes, every other statement that can be directly attributed to Joseph supported Letter VII.
- Yes, Oliver did tell Brigham Young about the records repository in the Hill Cumorah.
- No, Joseph didn't write unattributed articles in the Times and Seasons, so we can throw those out.
- No, it's not possible, feasible (or even a good idea) to concoct an abstract map using the text without reference to Cumorah as a pin in the map because such an effort is inherently subjective and depends on subjective interpretations of every term used in the text.
- No, Joseph and Oliver were not merely speculating. Nor were all the other Latter-day prophets and apostles who have spoken about the New York Cumorah.
This is merely an overview of the growing supply of solid information.
Hence, the need to get our act together and stop promoting theories of geography that contradict the evidence, along with Joseph and Oliver and the other prophets and apostles.