I don't think that follows. You can run a fully-functional X session, with an arbitrary number of windows, without any compositing. It's not some special case reluctantly added after people pointed out that the initial "you must fully double-buffer every single pixel every single time" wasn't actually universally a good idea. But even at face value... okay, so you'd like to extend the argument to say that not even Wayland actually forces you to composite? Because that's agreeing with my argument, just more strongly.