I think your point is a good one, but I'm not sure about the example.

It seems just as likely to be that the economist in question doesn't understand elements of football enough for his advice to be good.

I guess I should read the paper. But just because more often than not 4th down attempts succeed, does not mean they should be attempted more often. The gain of a successful 4th down attempt -- four more downs -- is much smaller than the risk -- giving the opponent's psychological motivation and good field position. So coaches should only attempt 4th downs when the odds strongly favor success, and a high level of success indicates that is what coaches do.

Now I presume Romer attempted to take things like this into account, but I guess what I'm suggesting is it is just as likely that he failed to do so properly, for the same reason we think it's plausible that professional coaches fail to properly consider statistics. Except at least the coaches have more experience and have been selected based on successful strategies, whereas Romer has not.