I don't think Watkins and Hayes put the defense in the "elite" category for depth as neither of them are probably future NFL draft picks.
They don't need to be high draft picks to make the quality of depth Elite.
Who would you rather have as your 2nd string DE taking ~300 reps this year? Kahlid Kareem who is a GREAT backup? Or Ade, who's never played college football? When you can bring in a back up like Kahlid who's arguably better than your starter, that's when you have elite depth.
Who would you rather have as your 4th corner, one of Troy Pride/Shaun Crawford/Nick Watkins, or Donte Vaughn who also didn't play last year? Same thing - say Watkins is your 4th starter. When he's arguably as good as any corner and you can bring him in at 4, that's elite depth.
It's about having those 2nd and 3rd level players be legit players. We knew we'd have that if Kahlid is the backup and Ade is the 3, we do not know what he have at 2, and we don't even have one at 3 now.
Same for corner. Same now for running back. These are massive losses to the quality of our depth, and it would have been Elite for the first time since 1990s IMO.