Agree with Bundy (who is a fantastic poster, btw) that there is plenty of talent to feed several teams - of course, need to remember that Big12 south teams aren't the only ones recruiting the state. So, some of those 4* players Bundy mentions as up for grabs between aTm, TT and OkieState are going to head to Michigan, USC, Auburn or Nebraska or wherever else.
The problem for aTm (right now) is that a group of those 2nd tier (that makes them sound lower rated than I think they are, but I'm not sure what to call them) are going to be in a mismatch against the 1st tier players - at least on paper.
So, while aTm might start getting better and better in terms of ability, it might not show up in W-L %. The result is that momentum then slows and some of those 4*'s start moving more towards TT or Baylor or whoever. So, unless aTm gets a few upset wins, they might just bounce up-and-down between 3rd-5th place in the division as they win/lose momentum every 2-4 years.
I think aTm should be consistently better than TTech, OkieSt and Baylor. They have the resources, fanbase & proximity to Houston to be a strong program. But, if they are in the business of fighting for recruits once the 1st tier players have been picked off, it's going to be tough.
All that said....get an upset win or two, or pull in that super special player (think Vince or Ricky or Peterson), then all bets are off. I just don't think "coaching up" lesser talent is going to be enough.