The same is true with phone numbers. You can migrate a phone number between carriers via Local Number Porting. The percentage of people that register their ow

The same is true with phone numbers. You can migrate a phone number between carriers via Local Number Porting. The percentage of people that register their own domains are in the minority, and probably are a very small minority. The bulk of the public use domains controlled by their email provider, and they have need of something like LNP. If email had a process similar to LNP to migrate addresses between providers, I'd agree with you, but it doesn't and nobody is pushing to do that either. Technically it would not be that hard to do. I'd love it if there was a redirect mechanism where attempts to deliver to a ported email address returned an SMTP code telling the sender to deliver a given address to another MX record. Email forwarding as currently implemented is absolutely awful as much of the information about the original sender (like IP address) is lost.