California and Texas are weak outposts of the MWC.Nevada's loyalty is divided between Reno/UNLV/PAC 10.Again again you mention that a few BCS schools are in small states so what.The NYC region has close to 25 million people ,which is 3-4 from Syracuse,UConn and Rutgers.That is more than your inflated 16.5 million for the whole mwc and the buying power in this region is large.
What you forgot to mention is that the LDS Church has 5.4 million people in the US. Many live in Utah, Idaho, Nevada, Arizona, and California.
Not all of the people in Utah a Mormon. So while UT provides 2.4 million of their entire population, they provide a significant share of NV, ID, and AZ population (not a majority by any means in NV, ID and AZ, but siginificant). So couple that with UNLV, which is the only game in town in a metro area 1.6 million you have a significant share of NV.
There is probably 3 million Mormons that don't live in either UT or ID. Plus you have Air Force which is the equivalent of Army and Navy with anyone in those armed services following AFA in sports. Both BYU and AFA provide some national stature to the MWC, beyond the 4 flagships that are located in the footprint. The 16.5 million is a well conservative estimate of their market.
It is virgin territory that doesn't have significant following for BCS conferences and the BCS may see that as an opportunity if the MWC meets the primary 3 criteria.