I agree and disagree. The inherent qualities of a more recent language (especially one like Scala which seems to be built upon a good foundation) may make a tea

I agree and disagree. The inherent qualities of a more recent language (especially one like Scala which seems to be built upon a good foundation) may make a team more productive in the long term despite the initial cost. However, what also counts in the long term is the structure of the codebase, and I'd argue that people with more experience in a language are better suited to build more long-term-viable codebases with less technical debt just because they know the language better. But perhaps that's simplistic.