Eventually the "fediverse" may end up even more loosely connected than it is. All that it really needs to be is decentralised/federated and open source/open protocol.

We're in the age of epic centralisation of the Internet, but it wasn't always that way. Hopefully we go back to something where there is much more diversity, much less corporate control, and much less need for monolithic platforms that need to support millions of users (and the technical challenges that come with that).

As far as money, I think people are much more likely to pay for things online if they feel like they have some kind of genuine control over them. i.e. it's a "donation" not paying for a service. Servers are pretty cheap these days, so even a big instance can get by on a few thousand a year.