You're taking a Jets fans opinion on Giants fans and adding it to your opinion as a NJ resident. LOL.
Just one question, why would any REAL Giant fan switch and become a Jets fan? Like, for what reason? Because the Jets were "winning"? You and I must have a very different definition of winning.
There are always going to be fairweather fans in a city like NYC. We have implants from all over the country looking to start anew, including with their sports teams. But as far as true blue Giants fans? You'd be hard pressed to convince me of that. Most Giants fans don't know Jets fans are alive, like beh235 said. That is, until they start running their mouths about AFC Championships and Mark Sanchize being better than Eli, etc etc etc. It didn't even take 6 games to go by this season before the Jets crowned themselves kings of New York. As if having a better record matters. For the most part, from what I've seen, Giants fans don't really care about the Jets. The only reason we ever root for them is b/c we have a mutual enemy, being the Patriots. Moreso, Boston sports in general. And since the Giants aren't in the same conference or division on occasion we find ourselves having to cheer for the Jets, b/c the hate is that deep. I've been a Giants fan 3+ decades and the thought of jumping ship as an option has never even crossed my mind, nor have I ever seen it from anyone whose fanhood seemed legitimate.
So perhaps they do things different on the other side of the Hudson. But over here, it's oil and vinegar.