Anecdotally, I gave Dvorak a try and became somewhat proficient, but ultimately reverted back to QWERTY for one reason: keyboard shortcuts! Control-C|V|Z are all transformed into either two-handed shortcuts or right-handed shortcuts. In either case, I can't copy/paste while selecting text with the mouse (since I'm right-handed). I now use Colemak ( https://colemak.com/ ) which doesn't have this issue and I'm quite ha…
For me it was the burden of typing 'ls'. I'm in the shell a lot, and the dvorak layout is very much _not_ shell friendly.
(I mean, to each their own, I use dvorak because other layouts hurt my hands, but I would presume there are better non-shell-friendly examples -- but interestingly, I couldn't readily find them since `mv` is also just the right hand, unlike its qwerty friend)