I don't know about respect. The data is on persistence of status. They can do this in many countries, those are just two I remember (besides England).

Direct records of ancestry are too scattered to piece together long timescales. What he (and collaborators) do is to find very rare surnames, in records at some distant time (e.g. Oxford graduation in 1600, high-status, or common criminals executed then, low-status) and then trace look for the same name in later data (e.g. Victorian wills, or today's tax data). Rare names give you a fairly targeted marker. One which the carriers are often unaware of.