I disagree. If your goal is to collect metals only for the purposes of returning to earth, then perhaps you are right in the short term. However, if those materials are used off-planet (or on-site) for the further production, it makes a LOT of sense. Once the foundation of production is in place, mining and building <more spacecraft, Mars habitats, ...> becomes almost exponentially more efficient to do off of Earth (especially factoring in time requirements). Beyond that, there is a good chance that future technologies will require 'rare-earth' and other precious metals that exceed quantities that could ever possibly be extracted here at any cost.

That's a closed loop. Mining asteroids is extremely valuable because getting stuff into space is very hard. Making it cheaper to put more raw materials into space will have the effect of... Making it cheaper to put more raw materials into space.

How do we profit off of this? Manufacturing?

I understand why you would want to build a widget factory in China, but what possible goods could we produce on Mars, that wouldn't be easier to produce on Earth?

I understand the situation of rare-metal shortage, but many of them are rare because extracting them requires uneconomical amounts of energy. Mining them from space (And good luck finding an asteroid with more then traces of Gallium) would still require uneconomical amounts of energy.

> I understand why you would want to build a widget factory in China, but what possible goods could we produce on Mars, that wouldn't be easier to produce on Earth?

On Mars? Probably none. In LEO? That might be a different topic. In general, you don't want to move up the gravity well if you can avoid it.

A naive person in me hopes that as space manufacturing becomes an option, the terrestrial manufacturing costs will rise significantly as people will no longer be willing to tolerate the abuse of humans and ecosystem alike that today's manufacturing is.

What the Wright brothers did also made no economic sense in the context of cargo planes and airlines.

Innovation is not just about making completely new things possible, it's also about improving the things you can do, making them cheaper: Making it so that you can do them in a way that does make economic sense.

This is just the first step of several. The first step is worth doing, even if you won't cross the finish line while doing it.

This stuff makes economic sense to retrieve at certain costs of space launch. As well as manufacturing some stuff (like optical fibers) in space, producing energy, sending nuclear waste there etc