CTL, your family is a shining exception. The Ridbaz, in fact, left Chicago declaring that Judaism would never take hold in America (on the other hand, the main claim of Mordechai Kaplan was that mitzvot such as Shabbat and kashrut had to be “relaxed” so that Jews could make a place for themselves) .
Sweatshops had signs “If you don’t come in on Sat don’t come in on Mon”. Until Torah uMasora was established after WW2 there were no day schools (all of the yeshivot you cite were for older boys – there was nothing for girls) and then they faced enormous opposition from parents who wanted their kids to be “Americans”). Everyone went to public schools, which were bastions of conservatism but also places for inculcating Xtian values. Even when I went to public school in the Sixties there was singing of religious songs near Dec 25 (I was able to get away with not singing by virtue of the fact that there were enough kids to enable me to hide in the crowd).
It should also be noted that merely coming to America at the time was often a rebellion against the rabbinic establishment as only the strongest received heterim. Their children very quickly through off everything. For example, a survey of Brownsville, Brooklyn (then an almost completely Jewish neighborhood) in 1940 showed that only 9% of the Jews went to shul regularly (Jews in Gotham p. 54). The growing discrimination against Jews in employment certainly hastened this trend. It was hard enough for a secular jew to get a good job. In fact, despite being at the top of his class in Harvard Nat Lewin was rejected by a series of firms when he brought up Shabbat. Finally he did what many others did and went into government service before opening his own firm.