> True. But we DO know the asteroids are valuable.
The only value of asteroid mining in the forseeable future is to support other off-planet operations, since the only time that getting anything from asteroids will be better than getting it from Earth is if you plan to use it outside of Earth's gravity well.
Parachute it. Drop it like a rock into a lake. Shape it and glide it in. That technology is in its infancy, and will end up unrelated to the cost of lifting delta-V. Its wrong to conflate the two.
The only value of asteroid mining in the forseeable future is to support other off-planet operations, since the only time that getting anything from asteroids will be better than getting it from Earth is if you plan to use it outside of Earth's gravity well.