I disagree with the article as well. Whenever I stumble upon really good engineers they are for the most part hyper specialized in what they do.

I would like to add that after I stopped saying yes to everything, my career took a upward trend. It wasn't until I said: you know what I'm python-django specifically django developer, and won't do anything else, that I started getting progressively better jobs in the area I'm actually an expert on.

Then there is the business cut cost part of it, which annoys the hell out of me. Most managers will (conveniently) tell you should be open to learning new things, because "personal growth"... the reality of the situation is that you will end up over working yourself to death covering responsibilities that should be for a new team mate.