Where baking is done can override volumetric measuring, even with sound, consistent technique. I'm a professional bread baker working at altitude in a low humidity environment. One cup of flour for me will weigh less than a cup for someone in a high humidity area. Parents and grandparents passing down volumetric recipes in the past were unlikely to experience inconsistent baking/cooking outcomes because back in the day succeeding generations were apt to remain in the same geographic area.
But yes, I did not mean to endorse measuring by volume—only that you can avoid much of the problem if you follow proper measuring technique. As I noted in my post, I personally use weights when baking.
As for the historical justification for using volumetric recipes: you’re probably overthinking it if you’re connecting it to geography, and especially if you’re connecting it to altitude. More likely the reason would just be that volumetric measuring was easier and cheaper to reproduce until quite recently. Scales can be expensive, can break, etc. Cups are cheap and durable.
And altitude may be an issue, never had to consider that.
I think there are other factors that affects the amount of flour you should use, such as the ratio of water already in the flour.
If you use fresh flour directly from the mill, you may not need as much water in the dough.
I also imagine the method of grinding the flour may make a difference.