>soon enough after that we will be able to build electric cars from kits

I'm skeptical.

An internal combustion engine is a complicated, engineering marvel. But a complete engine, as a unit, isn't difficult to remove/insert. It's big, heavy and awkward, sure (so are electric motors and batteries), but an experienced person can do an engine swap in a couple of hours. And yet there aren't many people building ICE cars from kits. Why not?

Because the drivetrain is only one part of what makes a good car good.