How many TEs have come out in the draft the last few years that everyone believed would be that "elite" TE, and they're all pretty much just guys. The funny part is, besides Gronk, most of the top elite TEs pretty much came out of nowhere (Gates - undrafted, Julius Thomas - 4th round, Jimmy Graham - 3rd round). Even the other top TEs in the league, outside of Vernon Davis / Jermaine Gresham and Martellus Bennett who were 1st and 2nd round picks respectively, look at the others: Jordan Cameron - 4th round, Jason Witten - 3rd round, Charles Clay - 4th round.
Given the production of some of the elite - 2nd tier TE's, these guys would've been re-drafted in the 1st round. You see how many TEs we've seen drafted highly the last few years in an attempt to replicate these results. It seems to me that the personnel guys in the league haven't figured out how to identify an elite TE. We got pretty lucky with Charles Clay I think. He didn't hold on to that possibly game-sealing TD, but he's usually pretty sure-handed.