How is that any different than reddit with all the r/X, r/TrueX, r/AltX, r/X2 subs? Whether they're distributed amongst one instance or many, it's functionally the same. Just like we already aggregate content from numerous sources, the fediverse also aggregates the communities too.
I'm subscribed to many communities/magazines in a variety of instances. And many of those I found through word of mouth on here or just by browsing "Hot". They weren't hard to find. I honestly don't see the problem. It's supposed to be splintered so no central authority has control. That's the whole point.