As I understand it, X11 has many inherent security concerns, including programs being able to read the contents of other windows and intercept keystrokes. Wayland addresses these concerns but at the moment breaks certain functions like screen readers, cursor warping, and the ability of a program to resize its own window.
I am curious as to how the display protocols of MacOS and Windows handle these situations differently. How does a program in those operating systems gain permission to read the contents of other windows, if at all? What is to be done in Wayland for these functions to be more seamless or are there inherent obstacles?
Not an answer to your question, but a (perhas naive) question itself: are keyloggers impossible on Wayland?
With appropriate sandboxing of apps so they can’t just LD_PRELOAD code into all other apps you run, yes.
No, they are not. If someone has enough access to install a keylogger, then they can just grant permission to themselves. This is mostly security theater, trying to turn desktops into phones.