Yep. A lot of these smaller families didn't have the manpower to withstand the indictments + the general attrition.
Not only that, but I do now think that most of their cohesiveness and "raison d'etre" came from one forceful key personality. The three most prominent examples I can think of are Balistrieri, Marcello, and Buffalino. So those families would probably have stopped being major players after those guys were out of the picture even if they hadn't been hammered with indictments.
