I'm going to take a not completely insane guess and say that it's an odd outcome of everyone going by their personal (usually first) name. Instead of 10 Jasons

I'm going to take a not completely insane guess and say that it's an odd outcome of everyone going by their personal (usually first) name. Instead of 10 Jasons, each with a different family name, you get 10 different spellings of Jason and never know the family names.