The NFL is a league, like most, of teams that, if they have star players, tend to win, and if not, the opposite is true. If a team has enough talented players, it will be a winning team, and if it has some star players and a large number of good players, it can be a championship contender.
The Patriots are a team in transition. Many players have been sent packing and replaced by presumably better additions, at least on paper. The rubber will meet the road beginning later in July, when training camp starts, and those players will play football for real.