You’ve lost the plot if you’re arguing making the playoffs is not a successful season.
Their second season was a teardown year where it was expected we would suck as we cleared cap hits.
I don’t consider 9-7 to be a very good season.
It’s barely over .500. Several of the Drought Bills teams managed 9-7 (and were objectively better than than the 2017 edition). The only difference between 2017 and those other teams was that the rest of the AFC sucked enough that year for the Bills to barely bumble their way in on tiebreakers.
But I don’t consider 2017 to be more “successful” than, for example, 2004, just because tiebreakers went their way and Andy Dalton made a play. Now if the Bills has actually done ANYTHING with that playoff berth, I would think differently about 2017, but they did literally nothing with it.