No, it definitely does. Features like disparate refresh rates are very difficult to implement in X11 so they weren't. Bear in mind we have exactly one modern X implementation, x.org, and it's very hard to add new features. The codebase is old and complex.

The main strength of Wayland is that it encourages competing implementations. There are many Wayland compositors. That might be interpreted as a downside, but what it allows is innovation and incremental improvement. Something that was just not happening with X.

You could argue that it could have happened with X. What you can't argue is that it did, because it didn't and that's not up for debate. That's just the truth.

And, it doesn't even matter anymore, because x.org isn't being actively developed in any meaningful sense anymore.