Forget using Asteroid resources on the Earth, use them in Space.
I see using Asteroid resources as part of ‘living off the land’ in space. Forget using Asteroid resources on the Earth. They would be more valuable used in space, supporting a spaced based infrastructure and to help build whatever we need. The less we have to ship up there, the better.
At first, it would be expensive to mine the asteroids. We would have to learn how to mine and process the material. Eventually it would be cheaper and easier as we gained knowledge and our technology improved.