I'm not so sure that this claim is valid as a general observation. Multiple times in my career, I have seen scientific code written by academics dramatically s

I'm not so sure that this claim is valid as a general observation. Multiple times in my career, I have seen scientific code written by academics dramatically sped up by developers who used parallelisation, vectorisation using SIMD etc. So in terms of performance, naively written scientific code is generally easy to beat in terms of performance for a reasonably adept programmer. That said, "enterprisey" Java/.NET software engineering shops can indeed make scientific code sub-optimal sometimes. Have come across that sometimes too but I wouldn't generalize.