My thesis is that procrastination comes from cognitive dissonances. And that's the reason, why I don't understand these articles. They make a "science" out of something rather simple. The reason I (as a hobbyist) "can't" write a book or finish a piece of music is that I have ridiculously high, idealistic standards when it comes to producing a work of art. I much rather produce nothing than something mediocre. I don't even feel bad about it. I embrace fatalism in this area. If I don't produce anything worthwhile, so be it. I can't help it but start one musical project after the other. On rare occasions I've got the feeling I am onto something. In that case finishing is no problem. It could turn out that nobody likes what I do but in that case it doesn't matter because I absolutely feel that I did the right thing.
On the other hand, there are professionals: people who create for a living. (I am not talking about extraordinary people like J.K Rowling or J.R.R. Tolkien but people who have to work every day just to fulfill a need of the market) If you decide to go this route then idealistic thinking is (mostly) out of the question. If I had to write a pop song or light fiction I'd just do it. All that is required is knowing the basics of your craft and top down planning and then you just work through the list like a maniac. It may be hard work but it's easy to do because there are no contradictions. It's like knowing that you have to walk 10k to get back home. That may be inconvenient but you quickly realize that you have to do it and then you simply do it.