You can't use people as slaves unless situation is so that everybody has to become slave. Also, you can't use people as a tool (without their consent).
There's not much to discuss. We've been there already with Hitler's Work Camps and Stalin's GULAG Camps.
> There's not much to discuss.
Since it's just an unrealistic though experiment, I wouldn't dismiss out of hand the idea of "enslaving" everyone for a short time for some kind of amazing outcome.
> We've been there already with Hitler's Work Camps and Stalin's GULAG Camps.
Ha. No. Neither of those gave enormous benefits to the world. And they killed people, not just put them through unpleasant working conditions. Completely noncomparable.
One can argue he had quite similar result in mind to the proposed electric-vechicle-enabling indentured servitude.
I don't think it would be excusable even if he avoided killing people while defaulting to raping and beating the crap out of them.