They have, but usually it is via introducing additional fees to services/transactions, eg:
https://www.astuto.ai/blogs/understanding-the-aws-public-ipv... https://www.wiv.ai/navigating-the-rising-tide-of-aws-pricing...
The IPv4 charge is a good one!
I thought this was to allow them to be more relaxed about the limit (5 per region) which is how they used to control fully free services that cost them.
But an increase for sure - they did note the supply of free ARIN allocations was gone
It's a matter of perspective, I don't do IPv6, when AWS decided to start charging for IPv4, I moved to Oracle Cloud.