The world will require competent c programmers for many more decades, if not for the rest of your life. Being an expert in c will probably pay far more dividends in the future than any of the “modern” languages.

That said, if you’re worried you can’t write web software or develop an app with the latest stack, then try one, I’m sure you’ll excel at it. Pick up python or Go and start writing something, you’ll be surprised how easily it will come to you