Really, they just had one year in the last five without a big guy in the middle. For several years prior, they had Pot Roast and then Malik Jackson. Pot Roast looked like flab, but it took a bulldozer to move him. Malik was a beast in his contract year. 
Agree there is way too much emphasis on chalk stats. 
Honestly, I think it’s very seldom that the front office isn’t unable to identify what’s needed. But there’s a limited supply, a salary cap, and 31 other teams who want those guys as well.
I think Elway has done an amazing job of filling needs and being smart about it. Most of us reacted badly, and Elway got blasted when Osweiler and Malik Jackson walked on day 1 of FA in 2016. In retrospect, Elway brilliantly let two teams waste $167 million on those guys. Letting Julius Thomas go was another good one. It’s hard to see in the moment, but the best move when it comes to “premier” free agents is often letting somebody else sign yours.