A jar of honey’s seal, it turns out, is the final factor that’s key to honey’s long shelf life, as exemplified by the storied millennia-old Egyptian specimens. While honey is certainly a super-food, it isn’t supernatural–if you leave it out, unsealed in a humid environment, it will spoil.
Final doesn't mean most important, and if that was the big secret, then we would be seeing many foods lasting extremely long times (millennia in this case), but we don't.
That points to the big secret being the chemical makeup, plus keeping moisture away.
From TFA:
A jar of honey’s seal, it turns out, is the final factor that’s key to honey’s long shelf life, as exemplified by the storied millennia-old Egyptian specimens. While honey is certainly a super-food, it isn’t supernatural–if you leave it out, unsealed in a humid environment, it will spoil.