On the other hand, a bunch of X11 issues were just listed, and X has existed three times as long. Some issues are architectural and thus probably not solvable,

On the other hand, a bunch of X11 issues were just listed, and X has existed three times as long. Some issues are architectural and thus probably not solvable, some are just persistent annoyances that must be difficult to fix and likely will not get fixed because X11 has so little active development anymore. X has enough issues that a good portion of the community said, "we've got to fix this". And frankly, I've used software from multi-billion dollar corporations that gives me more trouble in a day than Wayland does in a month.