Sure they do, especially with certain match ups. Dennis Gardeck is a worker and it sometimes pays off, but usually it doesn't. The guy has 17 sacks in 96 career games. He have recorded a sack in only 11 of those 96 games, with 5 games of 1 sack, 5 game of 2 sacks and 1 game with 3 sacks. Hard work pays off against certain schemes or players, but generally it’s not consistently. That is why we need exceptional players at certain spots and hard worker all around them.
QB, Edge, OT and IDL IMHO needs exceptional players. Then one or two at WR and CB. ILB has two hard working hard hitters. They are fine, but they'll look better with stud pass rushers on the edge and beasts on the IDL.