The Four Color Theorem does not claim that 4 colors suffice to color a planar map. Instead, 4 colors are sufficient to color any planar graph so that no two vertices connected by an edge are colored with the same color. For any \(n\), there is a map that requires at least \(n\) colors.
Ericsson, whose work is widely cited by 10,000hours rule proponents like Gladwel’s Outliers, did not claim nor does he endorse the rule. See more discussion at 10,000 hours +/ 10,000 hours .
References

Four Colors Do Not Suffice. Hudson, Hud; Marcus. The American Mathematical Monthly, Vol. 110, No. 5, May 2003, pages 417  423. www.jstor.org . blog.computationalcomplexity.org .
A collection of instances in which I believed something that wasn’t true. A reminder to read not to believe, but to weigh and consider .