For my entire life, the energy of human innovation has been focused on the individual: we have seen the advent of the computer, the cellular phone, and then the infinite improvements, iterations, and combinations of those technologies. When you read a "BLANK of the Future" article, whether that blank is filled in by "Car", or "House", or "Hammer", you can bet it has something to do with the microchip or wireless communication.
In fact, the only other trend that has had a major impact on the things we use has been incremental improvements in materials, allowing us to build things stronger and lighter. (Note, I'm sure someone could find a technology to prove me wrong on this, and I'm purposefully ignoring healthcare innovation because--well, because I want to.)
Now, as I've written before, what we have not innovated on is what I'll call 'collective technologies': things that affect a lot of people, but that individuals rarely 'own'. (Think railroads and other forms of mass transportation, or other infrastructure.) These have been improved in recent years, but there hasn't been anything like a major breakthrough: just incremental gains, caused mostly by improvements in materials and the introduction of the microchip into older technologies.
When I read things like this, then, about the need to establish an economic reason for further space exploration, I'm in complete agreement. But the author is stealing a base: there is simply no way, with the technology we have, that we are going to see space mining or any other sort of economic activity pay off until we have an energy source that makes space transit much, much more efficient.
Think of it this way: the ascension of oil as the dominant energy source (and coal to a lesser extent) made possible every single transportation improvement over the last 150 or so years. Before that we had very inefficient, unreliable wind, water and steam power. Fossil fuels represented an order of magnitude improvement, and it took about a century (until Apollo, arguably) for us to push the limits of where that energy source could take us. Since then, no major breakthroughs on collective technologies. Why? We're waiting for the next energy source that can offer an order-of-magnitude gain on the current standard.
And just so we can skip to the point, that ain't going to be fuel cells, and it ain't going to be wind or geothermal. Maybe solar can step up, if we create much, much, MUCH more efficient panels. Otherwise, it has to be fusion, or something the vast majority of us haven't heard of. But if you want to get humanity off this rock and into a solar-system wide economy, don't worry about what NASA is doing, invest in energy research.