I can't disagree with many of the points in this article. At the same time, Dave Grohl is still one of my favorite musicians. I don't listen to the Foo Fighters to hear raw, authentic rock and roll. I don't listen to the Foo Fighters for clever, insightful lyrics or innovative musical ideas. I can find that type of music from other places.
I listen to the Foo Fighters because they write catchy, accessible music that, at the same time, has an emotional appeal that spans across many different demographics. At one point, Dave Grohl was probably the best songwriter in the world, according to these parameters. The Foos last few albums have been a disappointment, but at this point I can't say I'm surprised. They still have a remarkably strong back catalog, and put on quite an entertaining show (based on personal experience!).
And yes, Dave Grohl's enthusiasm is also a big factor. He comes across as a genuine, warm guy that simply enjoys writing and performing music, and feels blessed to be able to do that. I think it's ridiculous to suggest he continues to perform and write simply to make money. Is it possible? Yes, I don't know him personally, nor do I know a lot about his business ventures. He certainly doesn't come off as money hungry though, and that in itself is rare enough these days that I treasure it. Sure, many people probably benefit financially from his touring and releasing music, and I think that in itself is great. Still, he doesn't need anymore money, and neither do his bandmates.