Here are two videos about Bill Gate's comments on expertise and Bill Gate's working routine. In the first video he supports the idea that timing is a significant element in expertise. However, he states that not everyone practicing for 10.000 hours will necessarily be an expert. He mentions the cycles a person should go through to reach the level of expertise. Imagination, talent, being young, open-minded, fanatical and lucky are also vital to achive this level.
https://www.youtube.com/watch?v=CsGihiSE6sM
https://www.youtube.com/watch?v=1Xhas1dXoNw