It should not be too hard to create a collaborative pixel board and accept input from anywhere in the fediverse.
That’s a super optimistic viewpoint. Handling that kind of stuff is actually a pretty challenging technical problem. Reddit themselves wrote a nice technical blog post about the how they built r/place and the challenges associated with it. Dealing with synchronization issues across federated instances makes the problem quite a bit more difficult.
A YoY inflation rate of ~10% is most assuredly not natural in most of the developed world. I fully understand why it happened, but that serves no justification for the negative impact on the lives of the majority of the population.