What users? I do work in research and this is what I see almost every time -- doubling the number of CPUs available for a simulation is trivial; getting someone

What users? I do work in research and this is what I see almost every time -- doubling the number of CPUs available for a simulation is trivial; getting someone to rewrite existing code to make it twice as fast on the same CPU is hard. I am not talking about interactive programs -- a slow browser is annoying. I am talking about scientific computing. This is just my experience, can you provide some counterexamples?