Vast majority of scientists is not able to write idiomatic Fortran, yet alone idiomatic C++. Scientific C++ code that didn't have an oversight from a professional C++ developer will be always horrible. Scientific Fortran code written without such oversight can sometimes be bearable. This is perhaps the main advantage of Fortran.
Eh, I'm talking mostly about the large scientific code packages that are being developed with millions of dollars in funding and large, organized teams. The people writing these sorts of codes know what they are doing and a lot of migration to C++ is because they are more familiar with it and it's easier to hire skilled people.
