I used to have that. Then all residential customers were put under a CGN, and you can ask for a dedicated, public IP, free of charge. I imagine 99.9% of users can't tell the difference so the ISP saved a lot of IP space, while customers are just as happy.
Yup, ISPs in countries that got a nice big block if addresses in the early days can still manage this. I have a cable connection that was originally provided by NTL (now Virgin Media). My IPv4 address changes about once a year now as they do upgrades/maintenance. It used to change even less.