This would also be possible with IPv6 (not with DHCP involvement, but with other mechanisms). But the issue is that some ISPs (and cloud providers) simply don'

This would also be possible with IPv6 (not with DHCP involvement, but with other mechanisms). But the issue is that some ISPs (and cloud providers) simply don't care or even actively drag their feet (since it may be in their business interest to do so for now).