Even the Linux nerds who customize everything about their computer are probably still using the QWERTY keyboard layout. I've seen a lot of "arch btw" but never seen "dvorak btw".
Typing is one of those things that is just experience. Grab a typing test program and put in the time. It took me a few weeks, starting with doing simple things like the equivalent of jkjlj; sets until my pea brain got the minimal amount of muscle memory to be able to use it in the wild. YMMV but I can still use QWERT as well, but it feels weird and not as natural anymore.
The problem with Dvorak is that it’s English specific. It effectively hampers typing in non Germanic languages. And I’m not about to be switching layouts every time I switch input locales.
I'm an Arch user and I did try Dvorak for a few weeks. I eventually gave up because it was a huge hassle switching back and forth, remapping game controls, remapping code editor key combos, and so many other remaps. It just wasn't worth the effort.
I'd say it's got less to do with making money off the status quo, and more to do with lack of money in any of the alternatives. Most people can't type fast enough for extra layout efficiency to matter, and even fewer people care.
Yeah. It's one of those things where while a different solution is technically better, the benefit doesn't come close to outweighing the effort of changing for the overwhelming majority of people. And so the status quo remains.
There is no "they". Manufacturers respond to whet people are buying, and try to predict where that trend will go. If that trend went towards different keyboard layouts, they'd do it. None of them have any actual vested interest in a given keyboard layout.