Why is the character of Jack Reacher so popular?

Jack Reacher, the hero of Lee Child’s wildly popular thriller novels who is finally coming to the big screen Dec. 21, fails to pass any number of smell tests, some quite literal. He’s a voluntarily homeless drifter who travels the hot and dusty highways of America wearing the same set of clothes for several days at a time — he carries no luggage, no ID, nothing at all but a toothbrush and an ATM card, occasionally replacing his clothes with brand-new ones, bought cheap â€...