[andyfox]

One thing left out of your analysis is that the raising got the blinds out of the pot. So fewer competitors and thus a diminished chance that a "lucky" flop will hit an inferior hand. And, in general, players in a game where they suspect the pot will be raised are less likely to limp in from early positions, also cutting down on the luck factor. The fewer players involved, the less chance a high quality pre-flop hand will be drawn out on.