Fans totally rejected the AAC because UCONN sucked *ss and never played above .500 in football and yes, it was awful for basketball. If UCONN Football had been remotely successful against Cinci, SMU, UCF, USF, Houston, Temple, Navy, Tulane, then it would have been a different story. Like you said, the AAC was a very good conference with no buzz but if UCONN had been winning and competing for championships, fans would have viewed it much differently.
Of course fans prefer to play in a B1G or ACC over MAC or Sunbelt but that is not happening. We can hope that UCONN jumps from one of the worst programs in the country to P5 level, but hope is a dangerous thing.
Another point: Fans of programs care about other programs in their conference. They follow each other. No one cares about UCONN Football outside of our fanbase and that has to affect recruiting too.