I can't believe the mistakes I make sometimes. With 3 championships in a league almost 100 years old, too great a percentage would be able to claim "blue blood" status. No one was calling the Patriots a "blue blood" before we beat Seattle. All we had was a run three titles in four years.
I'd like to think the Patriots are considered a blue blood, but there is no unanimous agreement on the requirements so it's a definite gray area. In the Pats' favor:
1) the most Super Bowl appearances
2) tied for the second most Super Bowl wins
3) the most wins of the old "AFL" teams
4) the franchise with the second highest value per Forbes (only behind the Cowboys)
5) a record six straight conference championship game appearances
6) the team and player (Brady) that hold the most Super Bowl records
7) the most colorful/bizarre history of any NFL franchise (a fan knocking down an opposing team's pass in the end zone, the snow plow game, the tuck rule, deflategate ... never a dull moment)
I'm sure I'm missing some things. The Pats are not just another Bengals, Titans, or Cardinals.