There is no way that Amherst is ever going to be anything worse than a top half of NESCAC program consistently. Amherst has great facilities, a great head coach, a great football tradition, limitless financial resources, and, along with Williams, it generally is going to be among the top choices among NESCAC schools for most of the guys it can get through admissions (a few will choose Tufts or Wesleyan, but generally speaking, Amherst and Williams are not losing a ton of recruits they offer to other NESCAC schools; Trinity is mostly recruiting from a different pool, but could also be more appealing to recruits when there is overlap). When Amherst had one REALLY down period in the early 1990s, the school felt the pressure and let in two absolutely loaded classes in a row (classes of 1997 and 1998) for an immediate turnaround. Otherwise, Amherst has been mediocre at worst and much better than mediocre ever year for decades now, and if it ever has a truly bad year, you can bet that it will once again correct the ship quickly with just a few tweaks to recruiting practices. And I really can't imagine that an Amherst alum (married to an Amherst alum) who spent his entire career at D3 sports power Emory is going to be MORE hostile to football than his predecessor was (to the extent she was hostile at all, which I didn't really see). Certainly, he's going to be VERY tied in to the Amherst alumni network ...
If you start seeing football recruits choose Bates, Colby, Bowdoin, Hamilton, heck even Midd, over Amherst, you can say that it is starting to fall. But unless Amherst eliminates TIPS for football (no signs that it ever will) or there is some sign that it's become unappealing for top recruits (there isn't), it's going to be in the top 3-4 in NESCAC most years. I doubt there will be many more back to back undefeated years like Amherst had during the Kelton years, that was an artificial peak enabled by Williams' total and rapid collapse, but I also expect you will rarely see Amherst teams below .500.