The New England Patriots, like every other team in the league, did absolutely nothing at the trade deadline. While this is the fault of the NFL and their unusually early deadline, it didn't mean that the Patriots were sitting on their hands. They were actively dialing their counterparts around the league, trying to make something happen.
Not every team wants to change. Not every team thinks they're out of the playoff race. Not every team is looking towards next season. Not every team wants to trade (and probably lose) with Bill Belichick.