Android users are not doing fine security wise, the OEM update model, shitty locked ROMs provided by some carriers, the unpatched vulnerabilities especially on older devices is a security nightmare, tens or even hundreds of millions are likely already compromised. Apple devices are much more secure in comparsion.

Until the epic took this to court, nobody has the balls to challenge Apple. Epic has standing to sue and is ready to fight it.

This is going to be decided in U.S. courts.

WTO is unlikely to step in, they do not take disputes at a company level, usually betwwn country , unless another country sues the U.S. government for unfair trade practices over allowing this WTO has no standing to take the case. I don't see any country taking it to them , that country will need to show damage to their own app developers, this is difficult as Apple charges the same for U.S. devs too.

The EU anti trust and competition does have standing to take it up, and in the past they have fought Google and Microsoft over similar things (promoting own products and browser choice respectively), but I have not heard anything till now. Perhaps epic may also sue/ file complaint in europe and they may take on Apple in the future.