The problem with small systems is that they go away when the maintainer gets bored, dies, moves to a new country, gets too busy with life, etc. And they give the owner an immense amount of control, which isn’t always good in a time of declining trust and increasing hostility. At some point you get tired of migrating or rebuilding.

These days I don’t really like hosting anything that isn’t either under my own control or on a decentralized system.

I don't buy it.

First of all, I don't use GMail or Outlook for E-Mail.

What would E-Mail/messengers/telco look like in small without federation?