In recent years the local dominance has also spread beyond the NFL to the other professional sports teams in Boston. Out of the Patriots, Red Sox, Celtics, and Bruins, no team has finished with a losing record since '06-'07. Assuming the Pats don't collapse this year, it'll be 18 straight winning seasons and counting for Boston pro sports. Not bad.
*As a side note, I wish I had enough time on my hands to calculate the data on A: how many NFL teams haven't had ANY twelve win seasons during the span in which the Pats have averaged more than 12 a year, and B: whether or not any other cities currently, or ever, can match Boston's 18 consecutive winning seasons across all 4 sports. That info could make both stats way more impressive. So if you happen to work for Elias or ESPN or something and have access to those numbers, feel free to comment.