When thinking of what seems to recommend Mesoamerica over North America as the setting of the Book of Mormon, it may be helpful to keep in mind the words of Thucydides (1.10):
10. Now seeing Mycenae was but a small city, or if any other of that age seem but of light regard, let not any man for that cause, on so weak an argument, think that fleet to have been less than the poets have said and fame reported it to be. [2] For if the city of Lacedaemon were now desolate and nothing of it left but the temples and floors of the buildings, I think it would breed much unbelief in posterity long hence of their power in comparison of the fame. For although of five parts of Peloponnesus it possess two and hath the leading of the rest and also of many confederates without, yet the city being not close built and the temples and other edifices not costly, and because it is but scatteringly inhabited after the ancient manner of Greece, their power would seem inferior to the report. Again, the same things happening to Athens, one would conjecture by the sight of their city that their power were double to what it is.
In other words, appearances can be deceiving. Because one civilization leaves a lot of stone monuments, while another leaves mounds, does not mean that the latter was insignificant, or incapable of civilization of sufficient complexity to have produced or inspired the Book of Mormon. Power, technology, and magnitude can sometimes be difficult to gauge accurately based on archaeological remains. And, as many a Mormon scholar/apologist (among those who support a Mesoamerican setting) will tell you, just because something has not been found, does not mean that it will not be found. The same may be said of the native civilizations of North America.
“I was hooked from the start,” Snoop Dogg said. “We talked about the purpose of life, played Mousetrap, and ate brownies. The kids thought it was off the hook, for real.”