ip addresses…. can’t take them with you?

remember a long time ago when cell phone numbers stayed with the company that issued them; to switch carriers you had to change your phone number, and inform everyone you know, what a pita!
Now ip addresses are still like that. If you want to switch carriers, you need to change your ip address and update all your DNS servers with the new info. When you have hundreds of domains using DNS servers belonging to a handful of registrars, that is a disincentive to changing carriers.
Why can’t we take our ip block with us, and have the new provider route it? Sure the routing tables would become a nightmare mess, but that’s gotta be great job security for someone somewhere…