These composers really wrote music for bass, tenor and screamer/soprano but later grudgingly re-allocated some of the soprano parts to 'contraltos', just to shut them up. And the contraltos did shut up, because they couldn't reach the notes. This is the reason nobody notices the 'alto' section of choirs: they are entirely silent, because the music that has been given to them was actually really meant for 8-old boys hundreds of years ago, when everybody was shorter and had far higher voices anyway.