LAPACK [1] is written in Fortran. It is still heavily used in scientific computing. And to be honest, I don't know if there are good alternatives for it in other languages (except for CLAPACK, which is just a transpiled version of LAPACK in C).
Numpy specifically doesn't require Fortran. (That was the reason for the original separation of numpy and scipy.)
Numpy will compile f2py (to allow running fortran code in python) and I think it uses the Fortran lapack bindings in some cases if a Fortran compiler is present. However, both of those are optional. Numpy deliberately avoids requiring Fortran in any way.
Scipy, however, uses quite a bit of Fortran in addition to C and requires a Fortran compiler to build.
At any rate, as you noted, it's hardly dead. Modern Fortran is a domain-specific language, for the most part, but it's quite popular within that domain (scientific computing and HPC).
It's also used heavily in R itself and in many R packages. In fact some people go as far as to say R is a wrapper around Fortran libraries.
So yeah Fortran is not dead by any means. Tons of people are using it every day, but perhaps not writing code in it. Just like your OS and browser are written in C/C++ but your applications might not be.
[1] https://www.scipy.org/scipylib/faq.html#how-can-scipy-be-fas...