BS”D
What caused the mass secularization in Europe was false messianism – Jews believed that the ridiculous ideas of the haskila especially as expressed through socialism and communism were the secular replacement for Moshiach chas vesholom.
Reform was not much of a factor outside of Germany until said malignancy was exported to the US. The Jewish communities elsewhere were probably more like the one where I live – all believe or at least identify with the main Jewish community which is frum, some of the wealthiest cannot observe because of social and business obligations but they support frum institutions and would not hear of Reform, some are learning from scratch and settle anywhere along the spectrum of observance from traditional to very charedi; most are traditional and respect Yiddishkeit. That is because they remember what was – from stories handed down, from former refugees who return to spread Yiddishkeit etc.