The problem is really more one of "we operated so long without paying and now, blam, everyone pays next year".

It'd be sort of like if github deciding "You know what, everyone now needs to pay $7 a month/user for github". Perfectly within their right, but also a little bit of whiplash for a large number of people.

The next question is if this will last. There's already competitors to docker (rancher/podman/various k8s on my box things).