How long will it be before they mandate IP address portability?
If ISPs collectively mandated trivial site renumbering technology,
it would never need to happen.
Unfortunately most ISPs are quite happy to let migrating customers
retain holes from other ISPs' PA blocks. Also, not enough people
point out that this technology is just as lacking in IPv6 as in IPv4.
This is the crux of the problem, and will hurt everyone.