What style are you referring too? If you're referring to Billy's "style" I'm going to have to pull your head out of your ass. It doesn't take more than a few months to perfect what he can do and then repeat it 200 times in shows. Just imagine if your arsenal consisted of contact moves, juggling and moves that you learn as a beginner and you trained that exclusively for 6 months. Firstly, fucking boring to do. Secondly, incredibly easy to master if you get past the boredom.
That applies to other freestylers that have limited themselves to less than 10 moves.
For starters, why is Billy Wingrove's style the first you mention? I don't hate him like many freestylers, but I know he isn't exactly the best. He's still better than many freestylers that make fun of him.
I'm talking more about freestylers like Abdellah, Mr. Woo, Sean, Abbas, Tokura, etc. For me to claim it takes just as much time, they must be doing something somewhat impressive. The idea for this thread actually came from a thread in the video section called Peru Champion Interview I believe. Example of a very solid freestyler, not world class by any means, but he is definitely very solid. A member expressed how he wasn't a freestyler, but he was a football juggler.