Wayland is a protocol specifically for compositing window managers, the point of it was to simplify the implementation of window managers that already existed a

Wayland is a protocol specifically for compositing window managers, the point of it was to simplify the implementation of window managers that already existed as X compositors, e.g. Mutter, KWin, Enlightenment. If other window managers weren't doing that then it wouldn't really make sense to port them to Wayland, because that entails also redesigning them as a compositor. I know many older X window managers never bothered to implement a compositor and just recommended people use compiz, compton, picom, etc. Someone could build a compatibility layer based on picom or something, and that has been talked about for a while, but I don't think it will happen unless somebody funds it with some real dollars. And I'm skeptical of whether people using those window managers would even pay for it at all, based on the comments here it seems they would rather put the money towards keeping Xorg alive.