It's asinine to write about and promote such a result as "10,000 hours"[1] when the result was really that it varies a lot from skill to skill. Using some constant number like 10,000 gives exactly the idea that there is some hard-and-fast rule to the amount of time needed to practice in order to attain some skill in some endeavour.

[1] Whether that was the author himself or the various people that that wrote second/third hand articles about it.