Imho email is missing a feature for nameless email addresses for when somebody just buys their full name as a domain name. If I get "firstname-lastname.name", having the email be "firstname@firstname-lastname.name' kinda ruins it.
they'll grumpily sign up to gmail just so they can get a verification email, and that'll be all it gets used for. Messaging their irl friends will be done in apps like Discord.
lol I ran a sizeable team around 2020 and I had to educate a couple of our new hires straight from college that they actually needed to check their work email, after they missed important HR related stuff and they had just completely not realized it was an avenue for company communication, with an assumption that everything was available on our heavily used slack.
If email was a commercial product, the company would have done something about that. Email died because it was an open platform, with nobody to address this systematic issue.
I've successfully renamed an old account with an email address I no longer liked. It works quite well on everything 1st party, but does have the potential of causing issues with OAuth on poorly-coded websites that key on email instead of user ID (ie. most of them). You do get to keep your old email address though, so it still ends up working fine in practice.