That article brings up a lot of good points. When those books say "Teach yourself X in 21 days" or "24 hours", I don't take that to mean you actually learn it in 21 days or 24 hours, but rather, that is about how long it will take to just read the text (outside of all the coding along you should be doing, too).
The "ten years" rule, or, as it is now referred to, the 10,000 hour rule is interesting.
Here is another article, not programming related, that discusses it. It brings up the good point that measuring in years is less effective because, for example, if you are trying to master the job you work full-time, it will only take 5 years to have been working on it for 10,000 hours. If it is a part-time hobby, it may take your whole life.
Of course, you don't have to be a "master" of programming to make a fun game. I have seen more than enough people prove that over the years. At that point I believe it becomes more about the quality of your help and resources.