Put a person from 1870s London in current-day London. At first they will be amazed by the technological advancements. Then they will be amazed by how dumb the average person has become. Idiocracy is a documentary, not a comedy.
Hmm, Gustave Doré's illustrations of London were 1870s. https://commons.wikimedia.org/wiki/Category:London_by_Gustav...
The intelligence doesn't shine out of all the faces.
Given most people in that era were undereducated and had stunted growth due to being undernourished and maimed by pathogens I very much doubt it