Note the difference between “can’t” and “won’t”.
They WILL. It will take time. Yet it will happen faster than we think. We can grow meat now. That’s a massive step. And one of the reasons we’re looking at all these asteroids is a way to solve the payload problem (get our raw materials up there, though of course there’s a processing challenge, but handle that ONCE and the whole thing become self perpetuating). It’ll happen. It’s human’s greatest trait, we’re always pushing on the envelope.