> Everyone I know in astrophysics or engineering who can uses something else--Python, C++, and Julia, are big winners. I know many other languages, but for eng

> Everyone I know in astrophysics or engineering who can uses something else--Python, C++, and Julia, are big winners. I know many other languages, but for engineering work I have started some projects in Fortran simply because it is a very good fit. Python is not fast enough, C++ is a huge mess, and Julia has just been released, it is not mature enough yet. You would be surprised of how many people are writing solvers from scratch. It is not the most common job in research, but it still is an active field. And your point about results mismatch is true, this is a very real problem, but independent of the programming language used. To give a concrete example, many people have reimplemented almost identical material subroutines for FEM packages and obtain different results, but this happens to people using Fortran and people using C++.