Comment by toast0

The small ISP that serves my home has six IPv4 prefixes and one IPv6 prefix.

The small hosting provider I use has I think 7 v4 prefixes, but could be one v6 prefix (if they supported v6 which they sadly don't). Maybe not --- a lot of their /22s are advertised as four /24s to allow for a DDoS Mitigation provider to attract traffic when needed; but it'd probably still be fewer prefixes with v6.

Not every ASN looks the same, but many of them would advertise a lot fewer prefixes if they could get contiguous addresses, but it's not possible/reasonable to get contiguous allocations for v4.

Since the routing table is organized around prefixes, if there is complete migration, the routing table will probably be smaller.