Interesting take, I love it. That said - do people play piano for 6-8h a day? Or, knowing piano players and their … let’s say “determination”: after how many hours do your arms get tired?
You have to gain a habit of holding your body and hands very specifically at a piano to not gain an rsi (which at the beginning does make you more tired, but like anything else you gain the needed muscles over time if you stick with it). Most people aren't that careful with their keyboard positioning and how they hold themselves while typing, so I do have to wonder if there's more to be done on the human side even with an unoptimized keyboard layout.
I do wonder what will happen to ergonomics in the upcoming VR-replaces-your-laptop revolution. Apple had some working steps highlighted in their ad for Vision Pro that would make a piano player weep
You raise good points, and just showed me what my fallback career should be: Herman Miller salesperson targeting just professional musicians. Proper ergonomics is going to blow their minds! The people who want orchestras to look they did in 1700s Austria will just have to get over it