XOrg was predominantly used as a useless middleman between a compositor and a window manager communicating with each other. Just because the wayland compositor is “one big important process” doesn’t mean that the whole architecture is more complicated.

Multiple IPCs make the whole stuff way more complex, there is a reason why we have a big monolith as browsers and not some `curl | htmlRender | jsInterpreter` Rube Goldberg machine — the unix philosophy is not the pan ultimate design, it works in some cases and is utterly broken in others.