This is FACT. There is a lot of attention given to NFL games and the lines are usually pretty sharp. This is esasily seen by the huge handle on those games.There's more opportunity in college on a weekly basis, Gold.
That fact alone makes it "easier" to beat, based on the math.
I could add to this, but I got shit to do, lol.
With CFB, there is less money and less focus. Opportunities always arise.