I became an expert after 2 years and 7 months and practicing about 4 hours a day on average. Pretty sure that's not 10,000 hours.
Are you talking about USCF "Expert" class? That is an arbitrary title for the rating of 2000-2200 and not necessarily what is meant by "expertise." Of course, one of the major problems here is that "expertise" is impossible to objectively define. I'm sure people would argue, though, that the 10,000 hour whateverthing would be referring more to GM/SuperGM -- those who are at the top of their field.
No adypady02, that's like 3,7xx or so. Question is does that mean you had more talent or cognitive ability than the average joe? I don't think you can give an exact hour of study/practice to be good at something like chess for example. For one mastery of chess isn't set in stone, chess evolves and what it took to be a good player back in the 1800's isn't what it took in the mid 1900's and surely not today. I think it's more practical to say that chess mastery takes a lot of diligent study and practice, the amount will vary by individual.