I am sitting here looking at a 50-line Fortran routine in our codebase that says

! MARK 1 RELEASE. NAG COPYRIGHT 1971.

It has been revised since then to use free form, structured programming, MODULEs, KINDs, INTENTs and IMPLICIT NONE.

If we can do it, everybody can. I have already mentioned some reasons that people don't do it. None of the reasons I have heard are "Fortran is too old and clunky".