>> When frum people were sending their children to public school, they left Yiddishkeit in droves.
So, we have undeniable both positive and negative effects of American education on Jews. I listened with kids to Ellis Island audio interviews and several Jews there said that they could not believe that it is possible to go to a free high school and also did not discriminate against Jews.
On the other hand, it lead to tremendous assimilation, it is no doubt that yeshiva/BY education saved a lot of people, but is not preparing them for modern life and for earning an honest living outside of teaching in the same yeshivos, which obviously can not accommodate everyone without an external source of funds.