Apple is know to cracking down abuse of developer accounts, so they could ended up playing cat and mouse game with apple. Also, the dev tools are probably licensed in a way that you can't use it legally after getting kicked out of apple dev program. Maybe epic can get around this by divesting unreal engine into a separate company. I think it's already done that (unreal is under epic international), but as apple was considering taking down epic international's account too, maybe that too is not enough.

You can use Xcode and the SDKs without even having an account! A free account is required to sign code temporarily to run on test devices. Apple shouldn't even get to know what is being signed.

Apple might be cracking down on people who sign apps for others as a service, publish signed stuff online, etc. but they literally have no way of preventing development of anything.