This is essentially a broad price increase without saying it as things stand today. Most AWS services require IPv4 and in most cases even if you don't require IPv4 there isn't even a way to turn it off.
Example: if you run load balancers you are going to pay for every single IPv4 address with no way to turn it off, even if you are IPv6-only. This means an ALB with 3 AZs (What AWS recommends), went from 20/mo to 32/mo and no amount of planning or optimizations can lower that cost.