I think the idea of 10,000 hrs of practice in order to become an...

I think the idea of 10,000 hrs of practice in order to become an expert, means AT LEAST that much time with no guarantees. Unless you've been exposed to accurate info, the correct skill set and been able to adopt the practices proficiently and consistently some can learn all the wrong things.

Its like a necessary but not sufficient condition to becoming an expert in the field.

Problem with the market is so changeable - not like learning medicine/surgery etc. Just when you think you've become an expert you get a rude awakening. Its a highly complex set of skills we need - there's such a long list, and all debatable!