The Sopranos clip is a great example of a coach or player being elevated just because they had some success in New York. It doesn’t have to be sustained success or even championship level performance. To be fair, it did help that the Sopranos was set in the NY/NJ area. Still, just do well for a NY team and you'll get pushed like you're one of the biggest stars in the country.
Mangini took a 4-12 Jets team and led them to a 10-6 record and a playoff appearance (the only postseason game of his career.) For that, he's the Mangenius and is offered a cameo on one of the most popular shows on cable. It's not like Mangini took over a team that had been struggling for years, though. Herm Edwards had the team in the playoffs in 3 of his first 4 years, including a 10-6 record in 2004. He was fired in 2005 after a 4-12 season and Mangini is a "genius" for getting the team back to 10-6. I believe the main takeaway is that the Jets Suck!