Thing is, the worldbuilding you do is largely independent of the mechanics.
Which has been my point all the way along. Just because the PC's meet 3 Deadly/Day encounters does not in any way shape or form mean that monsters only travel in Deadly groups. It only means that your PC's meet Deadly groups because, you, the DM, have decided on that pacing. It has ZERO impact on the rest of the world.
It's only when you try to force adventure building mechanics (which is precisely what the pacing, or XP/Day guidelines are) onto a larger world implication that you have problems. Once you realize that adventure building mechanics are entirely divorced from world building concerns, all your inconsistencies vanish.
IOW, just because your PC's meet two vampires, does not mean that vampires are common in the setting. It could very well be that they met the only two vampires in the entire setting. Unlikely, but, possible. Now, as I argued previously, you shouldn't be static with your encounter/day paradigm anyway. It's predictable and no fun. One day you might meet 3 deadlies and the next day you meet 7 Easies. Whatever. Mix it up.
But, at no point does that have any implications on the larger world. The fact that D&D game worlds have almost all been built first and then mechanics laid overtop pretty much shows the path here. Other than Eberron, none of the settings were built based on the mechanics. Because, quite frankly, the mechanics first model leads to very inconsistent settings.
Why? Why are we assuming mechanics are used at all? The DM simply rules the results and moves on. There's no engagement with the mechanical side of the game whatsoever. If I want that farmer to get eaten by the wolf, or the farmer to have a nice new wolf pelt jacket, it's got nothing to do with mechanics.
There is zero assumption of mechanical resolution here. The mechanics apply to the PC's and the PC's ONLY.