A friend sent me this link: All time NFL Franchise Rankings which you guessed it, ranks the franchises by the Misery-to-Joy index.
While the Jets are not say the Chicago/St.Louis/Phoenix/Arizona Cardinals, they are pretty far down the list. I think the most telling stat is that Weeb Ewbank who won the two most important games in the history of the NFL (the "Greatest Game" in 1958 and Super Bowl III) was under .500 with the Jets.
Here is a taste:
Save for one fleeting afternoon of glory in Miami 40 seasons ago, it has just never quite clicked for the Jets. They have fielded some very good players, but few that were ever great. They have had some very good coaches, but few that were ever great. They have had some very good seasons, but fewer that were ever great.
On the player front, even their most iconic players lean woefully to the overrated side: Face-of-the-franchise Joe Namath is in the Hall of Fame purely for the win over the Colts. His overall career numbers otherwise mediocre at best, even for his era.