Two things can be true at the same time. UConn hired Dan Hurley to do exactly what he has done and they did so when they were still a member of the AAC. Being confident in his own ability to build a program shouldn't be a knock against him.
Would he have been able to do so had UConn not moved to the Big East? We'll never know. I'm sure being able to sell the Big East brand has made it easier.
It's not unheard of to build perennial championship contenders in non-major conferences. Kelvin Sampson did so with Houston in the AAC (four straight Sweet 16s or better), Mark Few built on a foundation at Gonzaga and John Calipari did it at Memphis when they were in Conference USA.