I've mentioned my similar thoughts in another comment on hackernews but will repeat them here.

I think ActivityPub & federation looks like promising due to cost of cloud hosting going down every year. Thus allowing self-hosting to become easy and affordable for a lot of people.

However there are other trends that need to continue for federation to succeed.

- Continued competition in cloud hosting market not just in US, but globally

- Automation & simplification of monitoring, upgrades, and security patching

- Reducing the complexity of the federation software. Mastodon and Pixelfed are great, but I feel like the feature creep can make them difficult to maintain while self-hosting. Less software complexity = less upgrades, less package dependencies, less security issues