I think the fediverse is inherently different than the "normal" Internet. The way I'm thinking about it now is that each instance is a bit like it's own town, and the activitypub protocol is the road infrastructure connecting each town. There may very well be a group of technologists in Town A, but that shouldn't stop anyone from making their own group in Town B.

That being said, it's very beneficial to be able to gather all of these disparate communities into one place, and going back to the analogy, this would be something like a city center, where many people from smaller communities come together.

Perhaps in the future, we'll be able to create our own feeds (i.e not just subscribed, local, and all). I think that would be a solid way to handle things. Bonus points if those feeds can then be shared with others, so that they don't also need to go through the work of finding and subscribing to the individual communities that make up the greater feed.