I think the fervor is going to continue until the next MONSTER hit opens; and, based on an historic view, that is a long way out. And I don't think that another Disney rehash, no matter how good, is going to displace it. Although rich people will pay ridiculous amounts to see LMM before he leaves, that is because he wrote the show, not because he was a big Broadway star. The star is the show.
In my 50 plus year of theatre going, there has NEVER been anything that has entered into the national psyche like Hamilton. NOTHING. Not Hello Dolly, not A Chorus Line, not Phantom, not Chicago, not Lion King. The closest is Wicked with teenage girls (and I don't think there has ever been anything like that, either). There is no telling how long the fervor will last.
Even in its heyday, did anyone think the original production of Phamtom would run for 28 years (so far -- who knows how long it will run). The 'rules' have changed and will continue to change. And Hamilton fervor is going to continue for a long, long time, because it is one of a kind.