I think ht2´s comparison is very good. Think of a functioning Commission in the same way as a functioning UN, before the collaps of the USSR.

In the 1960s, Lucchese could count on Gambino´s support in one matter, while Gambino could count on Lucchese´s support in another matter. At the same time, Bonanno could count on Profaci´s support in one matter, while Profaci could count on Bonanno´s support in another matter.

On street level, yes the Gambinos for example were much more powerful than the Pittsburgh Family. But keep in mind that the Pittsburgh Family had it´s representative on the Commission, speaking for them. So in a sense the Pittsburgh Family did have some influence on the Commission. In real life, and in real life politics, a small country like Cameroon has no influence in the UN or in the security council.