I guess the trickiest aspect is neither of itch and Steam are based in Europe. But as game developers are so dependent on these services to sell what we create, maybe it could at least further fuel the idea that the EU needs to run its own non-US reliant payment processors asap (something which in turn would definitely put pressure on Visa/Mastercard too).
But yeah, even signaling to the EU that this is a big problem and could get bigger in the future feels important. It'd be awesome if you started something like this!