As already mentioned, people working from home would benefit from this a lot, and KVM monitors for two machines have been a thing for at least a decade (Dell,

As already mentioned, people working from home would benefit from this a lot, and KVM monitors for two machines have been a thing for at least a decade (Dell, Eizo, BenQ amongst others have been offering them so there’s clearly a market). And even if it wasn’t very used, the environmental cost of just one extra monitor would be many many unused ports.