Are you comparing 40years of graphical environment stability and global use with something that has been broken for more than a decade and now all of a sudden is portrayed as secure?
I want to start applications as another user in my own environment and my own system and wayland prevents me, while x11 allows me (together with many forms of sandboxing and containerization).
I have asked this question to all pretend to be experts of wayland and I have 0 responses.