My theory? Lots of quality teams allowed to sit in a sweet spot of the draft. Being a better team means not drafting for need, which means the ability to take the best player on the board (like CJ2K). It also means you can swoop on a guy who inexplicably drops to you there (a la Rodgers).
This... A million times, this! This is why I said that we were in, "A perfect drafting position," in 2011. The, "needs," that we had were at positions that were relatively easy to get late in the 1st, and we could have, "stolen," someone who had dropped.
This is also why I don't like trading up in the 1st round. A good GM will get good players whether he's picking 5th, or 15th. Generally speaking, your odds of getting a bust are pretty consistent throughout the first round. Trading up is the sign of a bad GM.