European supervisions

Question

Regarding Martin Brody's comments in post 10179, I learned growing up that European supervisions were generally more lenient than American supervisions because on the European culture and society. In other words, their reliance of these leniencies are concessions to circumstances rather than preferred modus operendi. These circumstances include an increased difficulty in obtaining basic food items that adhere to ideal (l'chatchila) kashruth standards, and a higher level of antisemitism that would prohibit manufacturers from putting supervision logos on product packages. Therefore, inferences from Eurpoean supervisions cannot directly be applied to America (or so the logic goes). Along the same lines, the story is related about the Chofetz Chaim that he was very lenient with regard to his measurement of a "rivi'it" because of the cost of wine & difficulty obtaining it. In order to make the mitzvah of kiddush accessible to the masses, he was very lenient in this measure, even for himself. However, once economics improved, the Chofetz Chaim was unwilling to show others his kiddush cup so that they would not be misguided by its small measure and assume that he held that volume to be normally acceptable. So how do we differentiate from "normally acceptable" p'saq and "concessions" (sha'at had'chaq)? Can we infer normally acceptable p'saq from the practices of European supervisions? This is more of a conceptual question, since R. Abadi ShLIT"A has already ruled leniently in these matters, and the practices of European supervisions is simply "field evidence" that these leniencies are practical and reliable. However, should you find time, I would greatly appreciate a response. Thank you and Kol Tuv, Jack D.