You mean like Lawrence Phillips or Ki-Jana Carter or Rashan Salaam or Ron Dayne or Curtis Enis? Seems like the top NFL RB's come from the bottom of the pile.
As a rule, NON-Ohio State Running Backs NEVER do well in the NFL. The exception seems to be Larry Johnson, but let's watch.
Eddie George, Keith Byars, Robert Smith being the big cogs in that example.....
I know I am missing one too.....
Without pouring through NFL statistics, I can't argue your point, but I think as a general rule, QB's have a tougher time making the transition from college to pro than running backs.