I'm not sure about that - Wayland hasn't exactly been a runaway success either. The 2 key issues with Wayland, the fact that it's a protocol, meaning a lot of

I'm not sure about that - Wayland hasn't exactly been a runaway success either. The 2 key issues with Wayland, the fact that it's a protocol, meaning a lot of stuff needs to be handled by the window manager that was handled by the platform before, and its opinionated design, that made it very hard to port software that wasn't designed exactly how it wanted to be, meant adoption was (and is) very slow, and still kind of ongoing. Mir didn't have these issues.