I think there are a lot of misconceptions here re “300” years ago, or before haskala. There was mostly one Jewish community, of which a typical member was a tailor or a peddler, not necessarily learned, or looking for humros. BUT, all stayed in Jewish community, and their children were still Jewish. Modernity created a challenge where uncommitted would leave, especially when there were economic incentives. We seem to have found two ways to deal with it: learn how to confront modernity on its own terms, or create a community that is totally separate, knows Jewish law and ignore the rest of the world. Both approaches are new, there is no reason to pretend our great grandmothers went to bays yaakov, both have pluses and minuses, and I don’t think we found the full response to modernity. Those who pretend that they did, whether super modern or super chareidi are both wrong.
And, yabia, Sephardim mostly avoided haskala, so you don’t recognize all these new movements as authentic.