Sure, yes, there's no reason this should be hard for your ISP to arrange. I guess it might be slightly painful for large ISPs say if you're a huge American ISP and customers can just up and move all their gear from San Francisco to New York and expect the IP addresses to stay the same that's kind of annoying to implement and the service for those customers will either suck (a user in New York finds all their data routes via the West Coast) or cost you more.

But in the general case, for a customer who is just using the Internet from the same place as last time, there's no benefit to changing their IP addresses and clearly there's no reason static addressing shouldn't be free, it's just like one database entry for them to do it.

I could imagine them explaining OK, you get static BUT it might change if you move home or something, and that feels pretty acceptable to me.

For what it's worth I get static IPv6 and IPv4 (although of course the IPv4 is a tiny block, only a /27 IIRC whereas I have a /48 of IPv6) but I'm in the UK and with a specialist ISP that cares a lot about this stuff.