Probably more of an answer than you asked for but screw it.

Money. Research money and resources. More available access to other information. AAU in and of itself means nothing, but the status and acceptance is generally expected to be indicative of very active and well financed research. The Big Ten is both an athletic and academic league- In so much as their members share resources. The Pac 12 isn't as formal, but they clearly care. 9 of 12 are AAU and 1 of the other 3 is missing it only based on the technicality of undergraduate admission requirements, which functionally mean nothing to the decision makers.

The purpose, at least for the Big Ten and BTAA, is collaboration and sharing of information, tech licensing, training programs, some funding and most importantly the value-added opportunities a university might reap because they could get access to assets and projects they might not have otherwise been able to obtain on their own. Even commonality of banking systems can be very helpful. The money brought in is enormous and the primary purpose of institutes of higher learning. CFB money is almost negligible compared to Washington or UCLA or Michigan's research funding. They *like* football. They want to be good at football. They'll even spend money on football, but...

It's chump change in the grander scheme of things. They aren't messing with that which brings in billions annually.

There are obviously a few exceptions in the midst, most of which were grandfathered in. But ASU, the "Dumb" Pac 12 school with Simpson's and Family Guy jokes about it, does more R&D than all but Florida, Aggie, Vandy and now Texas in the SEC as far as I can tell. And that's without a medical school (petulantly blocked by Arizona-favoring members of the BoR multiple times), which is normally the main driver.

And that's ignoring the Big Ten's unofficial affiliation with Chicago and Johns Hopkins, which is probably the biggest research institute in the world.

Or that Minnesota and ASU are deep in collaboration with Mayo, though Mayo isn't as big on research as one might think. But it's still the Mayo Effing Clinic.

LINK

Tables from 2019 available here.

TLDR: Most of the SEC schools aren't playing the same game, with a few VERY notable exceptions. The Big Ten passed on Oklahoma, but they'd be DROOLING over Texas A&M and UT. Football is just an ego flex and advertising for them.

This post was edited on 8/14/21 at 6:30 pm