Email definitely has its issues, but given that every other form of digital communication is getting worse and more locked down, I have no confidence that a replacement would be better. While increasingly difficult to get self-hosted email to be accepted by the big providers like Google and Microsoft, it is still great to at least have the option of hosting a universally accepted form of communication yourself.
my theory is that if rcs keeps advancing we might see "texting" kind of merge with email at some point.
at this point RCS and email are pretty similar on paper.