In the case of US, New York at 8PM would get electricity from California at 4PM. There would be some losses from transmitting power for such large distance, but shouldn't it be better than just wasting energy or storing energy even less efficiently?
To limit resistive losses you have to go to really high V -> massive pylons (there were some built behind the iron curtain).
But you still have capacitive coupling (and reflections after the TL is larger than $\lambda$/10 -> You need to go to very low f or even DC
But high V. DC is hard! and low f AC is massive.
Ultimately it hasn't been done because it hasn't been worthwhile.
"In July 2016, ABB Group received a contract in China to build an ultrahigh-voltage direct-current (UHVDC) land link with a 1100 kV voltage, a 3,000 km (1,900 mi) length and 12 GW of power, setting world records for highest voltage, longest distance, and largest transmission capacity."
(From https://en.wikipedia.org/wiki/High-voltage_direct_current)
So to minimize power loss in the cables, you want to minimize the current. In order to transfer the same amount of power, you need to increase the voltage.
Not sure about the pylon sizes.