Maybe, just maybe, this is already his plan. Running for President takes time. Ron is so conscientious about his Congressional duties; he's not comfortable just writing it off and missing all the votes. Being a Congressman is a full-time job. Running for President is a full-time job. Ron is quitting one full-time job. Could it be so that he can focus on the other?
In any case, it is certainly not impossible that Ron would run in 2016. Most everyone said that he'd be too old in 2012. They said "time to pass the torch," "don't be delusional," "he'll never run," etc., etc.
But he diii-iid....