Asteroids could pay for so much space exploration

These things alway assume prices are stable. But once you get dumping currently high-priced metals onto the market, those prices drop to the cost of getting them to the market.

If some common metals become valuable in orbit, the price at orbit matches the cost of lofting the same amount from the ground. That will be $20,000/ton pretty soon, or maybe even $10,000, but probably won't decline much from there until somebody comes up with a better way to loft it than rockets. A space elevator is one of the less practical of such ideas.

I like the idea of a wheel a few miles across, rolling in orbit so the bit closest to the earth is, momentarily, at rest relative to the ground. Then, a rocket just has to get up to that spot at 0 mph, and it can grab and get flung somewhere at twice orbital velocity; or hang on and ride the elevator to the hub. At the hub you would need ion rockets running continuously to keep it up, but they are cheap. To build it, the big wheel would need a fair bit of metal lofted to orbit. You might start with just a rotating stick.

Very likely Musk hasn't given a thought to this prospect. Like refuel Starship in earth orbit. Then refuel again in Mars orbit. Go grab an asteroid and refine it back on Mars. Send 20 tons of gold back to earth on Starship. The Mars economy could be sustained this way. Pie in the sky really.

Refuelling rockets in orbit would be a use case for water sourced from asteroids.

Will Bezos build space colonies? Perhaps that's an impetus to mine for steel in space. Would it be cheaper to mine aluminium from the moon and catapult it into orbit? A lot closer than an asterood. And purer?

One of the arguments against the economics of asteroid mining for precious metals presented is the cost of shipping rock down to Earth.

One thing I've always wondered, is it possible to have asteroids deliberately crash through the atmosphere instead?