Those are moonshot companies; if they work they'd have the potential to bring in trillions worth of minerals from space, but before they get there they'll probably require hundreds of billions of investment first. Plus they'd destabilize the market.
No doubt this innovation will occur once cheap and dirty mining practices are banned globally. Until then, any slightly more expensive and clean method has to compete with the cheap and dirty, and in the mining business, that makes you non-competitive fast.
This also seems to be underserved niche for start-up companies. From miners that I have talked with, this is a small-moving enterprise setup.