ymribriat: I can assure you that most prewar shtetlech were very strict about adhering to tznius, not having girl friends, not having mixed gender schools, secular studies were an afterthought – if they even had any, they certainly did not fraternize with the Goyim or the Reform, they dressed very conspicuously Jewish that you could differentiate a Jew from a gentile a mile away and, yes, they got married young and had many children.
It’s true some things weakened after World War I, but certainly prior to that it was very strong and even after WWI it was much better than we see in OOT America.