I'd argue that StackOverflow shows what developers have the most questions about. This means that ranking is influenced by the amount of experience people have in the programming field, and leads to languages people commonly use as their first languages showing higher.

Besides that it's also influenced by how good the language is at explaining to the user what is going wrong. Clear error messages mean the user uses StackOverflow less, while arcane errors would mean they need to look for longer for the solution for their issue.