I think that is a very valid question, and definitely an interesting one.
What I think is important to realize, is that last year was really something special for the jets. It was a convergence of a lot of good things that resulted in a fantastic year. They were absolutely a force to be reckoned with and were playing at a level where they could have won a cup and deserved it. That was incredibly fun to watch. It was also a rare occasion, and jets fans should NOT get used to seeing such a complete team, no fanbase really will get to be so lucky.
Because yes, the cap will take some from them, and it already has. They will have to change, and very likely will not reach the peak they already hit. That is what happens to teams when they amass a great deal of talent in this league.
That being said, it doesn't mean they will be crippled. They will still be a great team, they just won't have an embarrassment of riches to lean on by this year or next. Plus, while other teams will walk into this embarrassment of riches scenario here and there, they will be cycled out quickly as well, just the same as the jets have.
So my take is that you are right, the jets will not be absolute cup favourites for much longer than a year from now (if they even are now), but if you lower your expectations just a bit, they do look to have a great window built for the foreseeable future. Besides, no team will be holding that position for longer than a year or two.