I can’t speak for everyone but I make enough money that messing around with e-mail spam is not worth it, when I’d rather be playing my instruments or whatever.

I do my email through my registrar (gandi) so I don’t have to worry about free email going away, but before that I paid for zoho.

Basically the reason I selfhost is to save time, not to have to muck around. Luckily I knew ansible from work so it wasn’t that much work in the beginning to set that up for my services.