I didn't see anything extraordinary in the article either. The guy focused on what he wanted to do and improved through practice.

The best book I have ever read on outlining how learning works is Mastery by George Leonard. One of his points is that many people assume we learn at a linear pace and so get frustrated when we find we are not making progress.

He says that is false. We actually learn in short bursts. There will be a period of flatness, followed by an intense period of gains where you will plateau and then fall back a little behind you're highest point but above where you were before. This will then repeat itself if you keep up. The time frame could change as well. One flat period may be days while another may be years.

This seems to be exactly the same process as the guy in the article went through.