In the case of most projects, copy/paste code is not just because of the language. It's because of lousy programmers. I've seen large codebases which are made up of a full 40% duplicate code. There's no way to blame that on the language.
You're missing the point of the parent: There is no 'one true' metric. If you use different metrics (actual lines, logical lines, gzip'd size, etc) you may well find different correlations.
