You summed it up well, this guy needs to stay as far away from interviewing as possible. This attitude is why people can't find the 10Xers, they interviewing process is set up to filter them out. Your observation here:

Here's a clue: technologies change. By definition, anyone with the "right skill mix" won't have the "right skill mix" for long. Amesome people adapt. But how would you even know that if you don't hire them?

gets to the heart why they cant. 10Xers are not a technology they are personality and a attitude. Hell some of them are not ever that great at some of the technologies they use, but they know how to use the parts they need to get them to the finish line. They know the principles of elegance in clean code, and simple systems that are only as complex as they need to be.

These people are not showing up to the door of people that interview like the author, and if they do they are not taking the position and probably recommending to other 10Xers to go ahead and avoid the interview.

I get the feeling from reading the article, that the author has not learned how to spot technical talent and is growing frustrated with it.