I’m fairly sure it must take extra work to make dynamic prefixes. I’ve heard some weird justifications about localised routing. But modern ISPs generally don’t work that way at all. For example, my ISP has endpoints in multiple cities, and can fail over to another city if need be. All my static IPv4 and IPv6 instantly move with me in that event.
I am 50/50 between incompetence. Or so they can keep on charging extra for a static ip.
I’m fairly sure it must take extra work to make dynamic prefixes. I’ve heard some weird justifications about localised routing. But modern ISPs generally don’t work that way at all. For example, my ISP has endpoints in multiple cities, and can fail over to another city if need be. All my static IPv4 and IPv6 instantly move with me in that event.