It is because they have crap d-linemen at least when Jones was out. It wasn't the philosophy, it is because Ryan Grigson is a moron and cannot put together a roster.
Speaking of Grigson, if Wilfork is the smartest move for them to make, it is pretty much guaranteed that Grigson will sign anyone other than Wilfork. In fact, he might trade a first round pick for Haloti Ngata who the Ravens are looking to redo his deal. Ironically, even though Ngata is on the wrong side of 30, that would be Grigson's best first round pick move he has ever made other than drafting Luck was was a gimme (if he was to make this trade).