For an interesting critique of Gladwell and others, read James Delisle's latest book, The Dumbing Down of America.

There is no doubt that practise and effort and mental attitude are important to success but at the end of the day, innate ability also plays a role. I could train all day but I doubt I could beat Usain Bolt. How do I know (apart from the fact that running is not my strength)? There are talented athletes who train hard daily with excellent coaches, who can't beat Usain Bolt.

Practise will make anyone better, it might even make you quite good, but it won't make you gifted, as an athlete, as a musician or academically.