Well presumably, they'd change the outlets to 240V-specific outlets. We already have NEMA outlets for 240V single-phase applications, even in residential build

Well presumably, they'd change the outlets to 240V-specific outlets. We already have NEMA outlets for 240V single-phase applications, even in residential buildings. Of course, then you'll have the problem where someone moves into a new house and then they can't use any of their stuff because it doesn't fit into the outlet. Then they'll go to Home Depot and buy an adapter, which just converts the physical outlets (and has a big warning about not using for devices not rated for 240V), and use that with their heater or toaster or vacuum cleaner, and start a fire that burns down an entire apartment complex.