Fortran?? Sorry pal, the 1970s ended in approximately 1982 more or less, when Roland released the TB-303. Think a bit and C for yourself…
If you are talking numerical processing, let’s talk machine-language libraries running over specialized hardware. This is not a language issue, unlike producing specialized administrative and business software, where you need to deal with large databases and model your client’s (often contradictory and incomplete) needs in less time then you would like to.