it's not that the market doesn't exist, it's that practically none of the enabling technologies exist (for the case or the phone) and that someone lacks the capital to create them let alone even the foggiest clue what they actually are.
We know how to get to an asteroid, and we have some idea how to detect what it's made of. If you look, you'll see that these mining wannabees are working on the next few enabling technologies. The goal is to reduce one of the nastiest barriers to exploration and development of space for humans: the high cost of breathing, eating, and drinking. I'm glad we have machines like Curiosity that don't need to breathe, eat, or drink, but some day I'd like to go out there myself. A space civilization that gets its air, water, and food from Earth will never be independent (no matter what your political inclination) and is unlikely to even be viable, unless you count a few millionaire tourists as a civilization.
In its way, this is like the long-forgotten effort to invent and produce clothing, which made it possibly for humans to spread outside of the tropics.