As far as I know, the protocol is pretty much standardised and it’s now up to the desktop environments to support and implement it, and that transition took a lot of time. GNOME has already been there and on its way to winding down X11 support, KDE has also been building up its Wayland support too. Waydroid (Android container software) requires it, and Valve uses it for Gamescope on SteamOS too iirc, to give games a more predictable place to render themselves on. Everyone’s got a kick up the ass with regards to Wayland support recently, but for smaller, independent/non-corp backed or niche software, of course, it’s gonna take a bit longer.