I know a few years back the straight up winner in college and pro football took home the money at about a 3 to 1 clip...
I don't know how that figure relates to todays games, as I have pretty much stuck with totals.....I did chart the straight up winner covering the spread a while back and the numbers were about the same....pick the straight up winner, forget about the pointspread (of course get the best number that supports your position)....and get paid about 75% of the time....
If you don't believe me, look at your bookie sheet after a weekend, and circle all the games where the team who won the game also covered the pointspread....do this for a few weeks...
This is pretty general and doesn't go into specifics about injuries, o-lines, d-lines,home field, and all those things that help determine who is actually going to win.....
If I had to guess anything specific it would be rushing yards and the play of the offensive line....good rushing game opens up the passing game and also allows the opposing defense to be worn down and consequently caves in....nice to eat clock and protect a lead with the running game....