No, it would not actually be cheaper to bring raw materials from hundreds of milliions of kilometers away.

No, it would not be easier or cheaper to manufacture a space station in a hard vacuum with robots in the asteroid belt.

You are so wildly optimistic that it seems certain that you'll end up being disappointed.

Musk sends a rocket into low Earth orbit - something we did for the first time 70 years ago! - and suddenly you believe you'll see robots mining and manufacturing in the asteroid belt.

It makes me profoundly sad, to be honest.