As for "letting" others get better, who exactly in the division made some sort of big leap? Patriots signed Revis, but they also lost Talib. Jets signed Decker, but have no other real options at WR and still have no QB.
The Broncos were already a Super Bowl team and they are spending all their money to make a quick run as the window on Manning is closing. The draft won't solve everything, but free agency and bargin shopping is still going on. Sure only three new free agents have been signed, but retaining guys like Grimes and Starks is just as important.