However, in 2019 he is irrelevant, and no more than an entertaining curiosity.
I think you're very wrong. There are many people in this country that are appalled by the general immorality in our society and the uncouth nature (e.g Jess Philips) of many in the public eye.
I think that, even among the young, people yearn for a more stable, friendly, honest and respectful establishment. Something to revere.
Rees-Mogg may appear to be an anachronism to some, but he embodies the historic manners of which we were once proud and that resonates with many. An English gent.
Though I don't watch it, the fact that Downton Abbey has been so popular and is shortly to be a blockbuster at the cinema reveals much to my mind. Can't see Eastenders or Love Island doing the same.