Do you really believe that?
Teams give a player different amounts of opportunities for all sorts of reasons. Sometimes they split carries simply because they have different backs on the squad with different strengths and weaknesses. So, they put one guy in for certain packages and situations and another in for others.
Anyone who has been watching football for a while knows that it doesn't come down simply to "who they like most." Sometimes, teams have trouble getting their more talented players opportunities. Larry Fitzgerald didn't have a reception until the second half of the super bowl. Do you think that was because they don't really like him as much as Breaston? Sometimes, a team simply doesn't have any other viable options and will give players more opportunities than they would prefer.
Bottom line is that it is a falsehood to claim that Brown would be "wasting his time" at Oregon in preparation for the NFL. Brown has already excelled in the same system Oregon runs and there is already one successful RB in the NFL out of that system.