I would rewrite the sentence as:

"Intelligence & character of the masses are incomparably lower than the intelligence and character of the individuals."

During the lifetime of Einstein, successful and educated mimicked the values of upper classes, even if they just pretended. After the WWII the middle class values took over. Today even upper class pretends to be middle class. Try to appear busy and productive. The "character" and intelligence have little to do with each another.