Which is why email is an absolute nightmare and missing so many features and takes so long to implement the most basic security and privacy. Outside of business use, email has become the newsletter and password reset center because it doesn't work well enough and hasn't kept up.

The IMAP protocol is a known dumpster fire but getting jmap implemented over every email client and server is basically impossible. Gmail avoids this by just implementing their own proprietary protocol which only works with gmail and the web ui/apps.