Check out GFortran, it's 100% free as part of the GNU project. I believe the Intel Fortran compiler is also free (as in money, maybe not as in freedom). The speed argument does matter too--how many high frequency trading/fintech/big data/banking/engineering companies are built, at some point in the stack, on high-speed libraries written in Fortran? I don't know any numbers, but any company that uses numpy is transitively also using Fortran in their stack.