Earlier quoted context omitted.
That link is a blatant lie. Redirect each wayland client's stderr to a different term and you will see that the process (keyboard/mice input + graphics output) isolation is still working as intended.
It's not a blatant lie. There is probably no default install in which I would not feel it absolutely necessary to change every credential stored on a system if it ever ran a compromised binary and a new install from scratch. At best you are hoping that the malicious binary someone tricked you into running didn't also take advantage of an additional vulnerability to compromise everything. Keeping in mind that your adv…
In the real world, any secure desktop solution is going to require a reliable execution environment ("security is only as good as your weakest link"). If you don't trust the user to properly handle that, then you must ensure they don't do anything stupid or dangerous to themselves by restricting what they can do. For desktop applications this usually means to execute them in a sandbox (such as Flatpak). QubeOS tries to do something similar, but stumbles upon the inherently insecure design of the X Server, and has to work around it running separate X server instances for each unreliable X client.