Yes. IPv4 is actually a cost for Hetzner. You can see it already on some servers as an additional price tag.
But they will probably just up prices for the end users.
Though I think mobile providers are already having a lot of IPv6.
Unfortunately, they use CGNAT which is a nightmare for anyone who uses the internet.
I pay them £5 per month to lease an IPv4 address rather than sit behind the CGNAT sharing the IP with all of my neighbors.