Maybe the buyers started migrating to IPv6 when they saw how expensive IPv4 addresses are and there is a delay before they actually migrate. IPv4 addresses are way more expensive than I thought, upwards of $60 per address, jeez...

If you think they're worth $60 an address then you can make a fortune buying them at half the price at https://auctions.ipv4.global/prior-sales

At 5% roi though, even $60 an address would be $3 a year. Address owners typically charge far more -- Amazon for example charges $43 an address per year.

IPv6 is now up to 49% [1] - it's possible that there's just less demand for IPv4 addresses.

[1] https://www.google.com/intl/en/ipv6/statistics.html

My best guess is that the public clouds stopped expanding after the end of ZIRP because startups vanished overnight and demand dried up.

GPU instances don't need public IP addresses.

Pure speculation but could be at the end of zirp companies sold off IP assets / bankruptcy sales is depressing price.