There are numerous incorreact assertions in this article. I'll take them one-by-one.

That asteroids are too far apart:

They are far apart, but the energy needed to vist them is small, if one is leaving from a location that has similar potential energy - i.e., not leaving from a gravity well such as the Earth. The implication is that mining needs to be a space-based endeavor, not something in which one leaves from Earth to travel to each asteroid. The conclusion that it is infeasible to reach asteroids is incorrect.

That we cannot land on asteroids:

That is just not true. It is a matter of engineering. Just as the original Boston Dynamics robot had trouble walking and getting up, the latest one can literally dance.

That Musk is a huckster:

Musk is a man who has transformed the auto industry, as well as the space launch industry. Who else in history has done something on that scale? Calling him a huckster is worse than unfair. And there are many who share his vision, including very esteemed people. Look at the board members of the Mars Society - you will find professors and intellectual titans.

That there is no way to extract minerals in space:

The author simply cannot envision robot extraction machines. This reminds me of when I told people in 1997 that some day people would read books on their computer, and was told that would never happen. And here we are. And something did not get substituted: computers simply got better and smaller - they were embedded in phones and tablets.

A lack of imagination is usually the issue when someone says "we never will XYZ".