Sorry, for states other than California, this year, that should say all of the the time; And part of why every house is wired for 240 is because our dryers and hvacs all use 240.

True but the equivalent of that else where is the 415 V cooker circuit.

All the mains sockets in uk houses are 240v - this is whey you never see an electric kettle in US homes

We're really conflating apples and oranges here as the voltage is only half the equation;

By code, US 2 phase (120x2 == 240) is going to be wired with lower gauge wire to provide more overall electricity. Typically, the 240v is going to be capable of providing 600 total amps (though there are cases where 400amp is served); with a typical breaker at 30 or 40 amps. compared to a triple 415 providing 8 or 15amps.