I was stating a syllogism there: understanding and working with different coding styles is difficult, increased difficulty adds increased expense, and Perl supports many different coding styles.

As far as I know, nobody's done a comprehensive cost analysis of similar software built using different languages, methodologies, or architectures. Certainly nothing recent. I've harped on this before quite loudly and I think it's one of the reasons our industry can't be called "engineering".

People's individual experiences just don't make for good enough data because there are too many confounding variables.