Leaving Gmail for Mailbox.org

I wish there was something like cell phone number porting for email addresses. I don’t know how it would work on the technical side or how you could secure something like that, but the idea of switching email providers is too daunting, so I stay with Gmail despite abandoning all my other Google accounts and services.

You kinda get that with your own domain. I think that's the best you are going to get

Isn't losing your domain a huge risk for any common user?