There was an article on HN a while ago that claimed it was really ball point pen...

mcphage on Jan 7, 2017 | parent | context | favorite | on: TV anchor says live on-air ‘Alexa, order me a doll...

There was an article on HN a while ago that claimed it was really ball point pens that killed cursive... the writing style and ink viscosity meant that the speed gains from writing cursive were no longer true, and instead it became slower.