It depends a lot on how accessible those services are. I tried to host some git repos 5 years ago and it was a hassle (needed mostly private git and reviews nothing fancy). I tried again this year and using forgejo was extremely easy. I don't remember exactly what problems I had before, so maybe I got better at finding things, but this time felt more polished. Containers, reasonable defaults, good tutorial on how to start, took in total less than one hour. I did in the meantime an upgrade and that was really 5 minutes (check change-log, apply it and go)

Of course, lots of work was done in the background to reach this point, but I think it is possible. Will I make the effort to make that happen for a social network? No, because I am not using them that much.

Technically things become simpler (in the sense that you can do it "at home" and if you add LLM-s to answer you when you don't know some obscure option it is even easier), but identifying well the use-case, deciding defaults, writing documentation, juggling trade-offs will remain as hard as before.

Note/edit: something being possible does not mean one should do it, so I think it will depend on everybody's priorities and skills. I wish though good luck to anybody trying...