The NFL Draft is a crapshoot. Surefire hits become busts, and late-round rejects blossom into superstars. Every year, every NFL team spends millions of dollars on scouting... and they still get it wrong more often than not.
Teams have gotten smarter over the years, however. While the original trend was to trade up, attempt to obtain a higher pick, many have realized that the key to a successful draft is volume, which means trading down. The more picks you have — regardless of how high they are — the bigger the chance that one will pan out.
There is an economic side to it as well. Higher picks get higher salaries, so whiffing on one can set your team back even further. The opportunity cost is higher than simply the player's salary, as it prevents you from signing other players under the salary cap. There is a sweet spot in the draft — the middle of the second round, where you get the most quality for your dollar. This is where the smart teams try to collect their extra draft picks.
Believe it or not, that was scientifically proven... by a freakin' Nobel laureate, Dr. Richard Thaler! It was all in his 2005 paper, "The Loser's Curse: Overconfidence vs. Market Efficiency in the National Football League Draft."
No, Thaler's didn't win the Nobel for that specifically, but here's hoping some general managers give that paper a read...