[jyoung8607]

The controllable shutoff valves are already a thing, on the market. They even measure flow rates and look for slow leaks and notify you in an app.

Draining the pipes isn't that simple, and even if you did, you still have things like a water heater, toilets, softeners, filters, and expansion tanks. You also wouldn't get the water sitting in drain traps; winterizing a house or RV involves pouring a little RV antifreeze down each drain.