If you looked at an Ashkenazi Ben Torah from 250 years ago (i.e. pre-haskahah), it would look amazingly like a modern day hareidi. It is the secularized Jews who changed.
Those claim that the “hareidi” movement is a modern invention is part of the “big lie” of the non-orthodox Jews (including some of the modern orthodox) that Torah and Mitsvos are a recent creation and that being Jewish is function of ethnicity and social customs (including support of left-wing political movements, among other things).