Los más ricos

Question

Why is it “los más ricos” and “los más listos”? If the assumption is that we are referring to people, (la gente or las personas), should they not take the feminine form?

Accepted Answer

Hola Stuart
When we talk about people in general and there is no noun/antecedent we use the masculine form in the plural; this doesn't only happen in comparative/superlative sentences like this one in the lesson, but also in other sentences. I imagine, although not entirely sure, that we use the masculine form as in referring to "los hombres más..." which refers to a general men and women but used the masculine as default. 
Los más ricos tienen que pagar más. (= la gente más rica) 
Rich people (the rich ones) have to pay more.
Los pobres son muy desafortunados. (= poor people, la gente pobre)
Poor people (the poor ones) are very unfortunate.
Debemos respetar a los mayores. (= elderly people)
We must respect old people.
I hope this clarified it.
Saludos