Double AA developers were the backbone of the PS2/GC/XBOX generation. Besides their creative outlook, they existed at time where it was possible to bet on middle sized production that'll take around 2 years top to develop without being labeled as "indie", and thus relagated by companies and consumers alike to the medium's kiddie table
I guess studios like Team Cherry and Yacht Club Games fall into a similar position but, contrary to the early 2000s, they're standouts and not part of the norm