Earlier quoted context omitted.
Because there must be a coordinated effort to change the default or at least increase the diversity of layouts. Otherwise it's like teaching esperanto, putting them into a very small minority for little benefit. Even as a technical user for decades I find it too burdensome to swim upstream with a niche layout, and I already have remapped copy-paste.
well, all we can do, is all we can do… if swimming upstream is that hard (and i agree that decades of professional usage on a X layout is hard to give up); at least when teaching someone you could say something: “here is the layout you should use! i know mine is different and i can type typewriter with one row in case i want to impress someone but yours is better, like minor chances of getting a RSI and general effic…
As more jobs come to benefit from shortcuts, QWERTY becomes more entrenched.