subject to a massive step change in battery efficiency.
You and I could do that too
A 1000HP 3-phase brushless motor is tiny. At a guess, about 1ft long and 2ft diameter if you want a low-RPM direct-drive solution. Weight perhaps 50-100kg (i.e. a fraction of a PT6).
The controller would be about 1ft cube; weight about 10kg.
Just need a battery................
Oh BTW you will need one other thing in the long term, to generate the electricity if this idea becomes popular:
Nuclear fusion
Actually that will prob99 come, within our lifetimes. It already works, for a short while.