Go for it on 4th down?

Since I'm taking a Decision-Making course in which exactly this sort of analysis is used, I was intrigued to read about this possible paradigm-shift in how to play football. Basically, never punt and rarely kick fieldgoals. Statistically, it makes sense. So why don't people do it, pretty much because coaches are afraid of looking stupid. It's similar, I guess, for why basketball players don't shoot freethrows underhanded even though the percentages for success are apparently higher (according to an SI story I read awhile back).

Note, by the way, that Tony Dungy did just what these stats say he should at the end of the recent game against the Chiefs (went for it on 4th and 1 near the end zone instead of kicking the "go-ahead" field goal). Everyone was saying that he was crazy . . . until it worked. Then he's a genius.

http://freakonomics.blogs.nytimes.com/2007/11/19/when-economists-talk-pulaski-academy-listens/