> it's hard, impossibly so, to construct a world where nobody with wrist mobility problems will ever encounter a round doorknob they'd like to open.

its not that hard to get to 99.999% though.

stop selling door knobs, or doors that accept round knobs. add incentives to swap or return round knobs. include checks for round knobs both for building inspections and insurance.

you wont wont get the last couple people that build their own doors and machine their own knobs, but thats gonna be a really small segment