Here’s the sticking point imo: the youth will always drive the direction of the internet, and they are an implicitly destitute demographic.
Corporations know this and so create “free” platforms where the youth can congregate and share content (and of course the corp profits via other means). POSSE works for marketing teams, but the idea of everyone owning their own domain name is just not gonna happen. People don’t even pay for email.
The only way the fediverse can compete with TikTok and the rest is if older users with a bit more money subsidize the younger users who may not even have a debit card. If the money invested by the total fediverse userbase isn’t enough to fund the service for all users, then it will fail vs the for-profit options. That’s how I see it.