Startups seem to have more of these types and big companies, fortune 500 sized seem to have almost none.
As for how it betters oneself to learn, you cannot know until you learn it. The new tech exists because someone tried to solve the problems of the past, sometimes it works. You can't know the benefits of object oriented or functional programming if you are still writing the same cobol you did in the past or for a more modern analogy you will need to stand up more apache servers to get the same throughout if you have never learned about nginx.
Double signed. Barely anyone is using his free time to learn more than needed at the workplace (which means the employees are stuck at the "minimum knowledge level"). And this is not just true for the IT branch.
One the one hand it made me feel a bit less stressed and a bit more confident about my own abilities. On the other hand it was a warning for me to keep trying to find the fun and challenge in my work, to treat it like a craft and not just a job, because every single one of these developers seemed to me to have relatively low job security, and I couldn't imagine many other companies hiring these people...
I think article is a bit naive. Nerds love learning for sake of it, but that is not usual. In what way the Expert Beginner could do better? Collect even bigger pay check? Or do less work for the same salary? Being N times better developer does not usually bring N times more rewards.