Have they, though? They've improved, no doubt about it, but improving on shitty doesn't necessarily mean one is "really good".
2015: I consider this draft a big swing and a miss. Sure, they got Byron Jones - who should be a cornerstone of the secondary for years - and maybe Gregory can stay on the field. I'll concede Green a medical red shirt and allow for him to be depth on the O-line and possibly a replacement for Doug Free. So that's one surefire player and two big question marks. To say nothing of the fact that they actively avoided running back, a position that had players all up and down the board. Big, fat F.
2014: Hard to argue with Martin, Lawrence and Hitchens. Though Lawrence now has the dreaded "can't stay on the field" label (which, by the way, gives them a matching set at DE) and Hitchens appears to have injury concerns of his own. No 3rd or 6th round picks in this draft make it impossible for it not to be top-heavy. This one's an A-, solely for the presence of Martin and the avoidance of Manziel.
2013: Three long-term starters came out of this draft. But this draft also saw the head-scratching decision to select Escobar in the 2nd (perhaps trying to keep up with the Kraftses?). That, alone, knocks it down to a B.
2012: Claiborne is still a starter by default - one has to wonder if the coaching staff saw enough improvement in him to stay away from Ramsey - and Crawford only became a starter a couple years after being drafted. By no means a slouch, he turned out to be the anchor of this draft. Wilber is a situational player, at best, and Hanna must have pictures of Jean Jones in provocative poses. Either that or he must really suck at blocking. I only give it a D because there are still four players on the active roster.
2011: I hope the Jaylon Smith situation sounded familiar to others, because that was shades of Bruce Carter to me. Perhaps it's because of where they went to school but I haven't heard a fraction of the outcry that I heard when Carter was drafted. Which is weird because Carter was guaranteed to play at some point - Smith, not so much. This draft is weird because only one of those players drafted in that draft is still on the team, even though it was only five years ago. Still, this was probably the best draft of the bunch.
The worst part about going through that list of picks is that they've managed just two significant contributors in the 4th round or later (Hitchens and Harris). Randle was drafted in the 5th round but we all know how that ended up.
So, if I may pick a nit, they've been "pretty good" not "really good". Unfortunately, they seem to be going back to their old tricks with the past two drafts at a time when they desperately need players. Combine that with an awful cap situation and we're almost guaranteed to see them struggle to get their heads back above water this season.