My taiji teacher Wang Hai Jun is basically saying the same thing. Do the form to develope internal power. Push hands and application is not that important. I think Dan is working on a more direct route,he is really on to something. The main point, solo training and knowing what and how to practice. not so easy, but Dan is trying to make it more clear.
I wouldn't totally discount push hands once you have some understanding of these skills. If when doing push hands you are trying to tie up your opponent's limbs, or overly using a lot of muscle it doesn't help train these skills. If you are using it as a means of understanding how to ground, negate, or redirect forces solely utilizing internal strength gained through solo training or other partner exercises, it is a valuable exercise applicable to grappling as it is merely a short form of stand up grappling.