There is no "we" that's empowered to do anything on the fediverse, and that's by design.
You, as an individual, are free to start or register with whatever instance(s) you want and start, engage with, subscribe to or block whatever communities you want. And all the other users here are exactly equally free to do any or all of those things.
It's safe to assume that over time, activity will tend to concentrate in a few specific communities, and that most notable topics will come to have a dominant community. I think, snd self-evidently many others also think, that that's something that should happen organically over time rather than being forcibly implemented by some authority. But more to the point, that's something that only can happen organically and over time, since nobody has the authority to do it any other way.