Sorry if I came across as condescending, I assumed you genuinely didn't know. Part of the reason why those services never caught on is precisely that barely anyone knows them.

I disagree that more federalized always means better, because it has serious issues:

1. What if you are offline? I'd like it if messages would eventually find me even when my computer is off, or I am in a remote area, a basement... even worse for file sharing.

2. Power. Modern always-on devices like smartphones are so power efficient because they mostly are sleeping in a standby mode. Every now and then, they wake up, check if something important happened, and immediately go back to sleep. If you want to serve data from a phone, you need a way worse running / asleep ratio, meaning a lot more battery drain. A central-ish server can efficiently do the small bits of work from many people in a place with plenty of electricity and on hardware that is suited for it.

3. Discovery is a hard problem. Having one or more central sources of information simplifies things a lot.

4. Management/admin effort. Instead of hundreds of slightly different installations, you have one, maintained by a few people who know what they are doing. Much more efficient.

But for example, all of the things I mentioned can be self-hosted. Granted, some like IRC are not federated in the modern sense of the word, but I would argue that "any single group of friends can set up their own server with a raspberry pi in someone's closet" is already pretty good. Especially if your goal is to avoid the corporate surveillance state or censorship.