BYU is a weird case in a lot of ways, some of which I mentioned, some of which I didn't.

BYU's viewership struggled by virtue of independence. We played a lot of bad teams...and we also weren't playing for much. Even Cincy, Houston, UCF, Boise (while playing mostly G5 teams) at least were playing for something (better bowls, conference championships). For BYU, after the first loss the rest of the season became a glorified exhibition.

Also, given the LDS affiliation, BYU is one of the few schools that draws outside the 100 miles radius. Sometimes we overemphasize this*, but it's a factor that absolutely DOES exist and isn't accounted for here

Given all that, I'd focus less on where BYU specifcally ranks and the general ranking of others and what that means for realignment

*There are nearly 17M LDS in the world, but only 6.7M in the US. And activity rates are about 40% within the US and 30% outside the US.
So that leaves approximately 2.68M active LDS in the US (1M of those in Utah) and 3M active outside the US.

So that's 1.7M active LDS members outside of Utah, but in the US, many of which have their own team that they follow or aren't interested in college football. Active members outside the US are much less likely to follow college football (it's pretty much a US sport) and even if they do, aren't going to watch through the same sources. So 1.7M isn't a huge number considering we started at 10x that (17M).  But it is enough to represent about a 60% increase in "market size" and adding that would be enough to bump BYU ahead of Cal, Louisville, Purdue, UCF, Mississippi St, Virginia Tech and NC State, maybe even ahead of West Virginia