Chaim Eliezer, regarding the E. European Jews who came to this country during the turn of the last century- you are right that many gave up the fundamentals like shabbos and kosher, however I’d like to wonder how involved they were in Europe with their Yidishkeit. There is nothing wrong with a healthy balance of culture, arts, etc—- but for far too many Jews, the arts and theater became the Ikkur of their lives, not the side dish. We still see the stubbornness today in 2018 with non-observant obituaries where the deceased requests all charities go to the city’s art or music museum and NOT the yeshiva, day-school, or synagogues, or even the local JCC. Reform and Conservative Synagogues can’t be surprised why their funding is becoming limited, when many of their deceased members request donations be sent to the arts.
So from cradle to grave those types of E. European Jews were more involved with culture and arts than with Jewish involvement- can we really consider them FFB?! —- Most likely I’d consider their children BTs (if THEY choose the privilege of becoming frum)