Why can't we do both? On the one hand, we obviously need better techniques to maintain and improve upon code bases in languages like C. They aren't going anywhe

Why can't we do both? On the one hand, we obviously need better techniques to maintain and improve upon code bases in languages like C. They aren't going anywhere anytime soon. But why shouldn't we also pursue improvement to the programming language state of the art? And if we find improvements, why shouldn't we use them? I'd be very sad if 50 years from now C (or Rust, for that matter) is considered the final word in programming languages.