I don’t understand the question. Pretty much all fediverse software was built with federation in mind from the start. They all started from scratch afaik, nothing was built on top of a centralized design.

They also happen to perform similar functions as earlier centralized websites, but that’s simply because those are the ways that people commonly prefer to use the internet. People use it to share photos, stream videos, connect with friends, microblog, blog, browse content aggregators, etc.

There could definitely be new paradigms of internet usage waiting to be discovered, but if the fediverse can’t even replace the existing functionality of the web first, it’d be very ambitious to start building brand new types of sites already.