A company I used to work for has spent 30 years trying to migrate FORTRAN code to C. I was not involved in the project, so I don't know the details, but the gi

A company I used to work for has spent 30 years trying to migrate FORTRAN code to C. I was not involved in the project, so I don't know the details, but the gist of what I was told is that there are edge cases where FORTRAN stomps C in every performance metric. So you can make decent progress for a while, but you'll eventually hit a major roadblock that halts progress.