When I was growing up I used to help run the mail servers in my dad's small-ish datacenter. One of the things we were commonly plagued by is that the email ecos

When I was growing up I used to help run the mail servers in my dad's small-ish datacenter. One of the things we were commonly plagued by is that the email ecosystem is a giant fiefdom gated by large providers to fight spam. If you end up on their lists, justifiably or not, it's non-trivial to be removed. The other point is that providers like GMail use custom protocols that improve the mail experience quite a bit. Nowadays I use ProtonMail and I get most of the features that GMail gave me, with the added benefit of not managing the blacklist situations.