Programming languages don't die, they might become less relevant over time, they might adapt and evolve, but they don't die.
A few examples:
- Assembly (1947) is still around, and still extremely relevant,
- Fortran (1953) is still around,
- Lisp (1958) is still around, in several forms and flavours, and it's fairly popular,
- COBOL (1959) is still around,
- BASIC (1964) is still around, but that's mostly Microsoft's fault,
- SQL (1970) is still around and extremely popular.
Obviously, none of us can predict the future. But if Fortran is still around after almost 60 years, we can safely assume that C isn't going anywhere in the near future. Even extremely niche languages never really die, if they were useful once chances are that there's always be someone who'll use them in the future (or some variant of them), even if only for academic purposes.