For many years it was just that I didn’t trust anyone not to hand my data over to someone else, whether that be governments, companies, or (unintentionally) hackers.

Nowadays I would probably trust Proton Mail, since they have pretty good encryption. But as you point out then I would be dependent on a provider.

Currently I mostly have problems when I lose power or when my ISP renumbers. Probably I should just migrate and save myself pain from Google and Microsoft making it hard to send mail to their users (which is most people on the planet).

I’ve been running my own email for 25 years and wouldn’t recommend it to anyone. 😔