Maybe depends on the project. Writing a web API in C almost certainly isn't pareto-optimal. A linux/raspberry-pi driver for your hobby-project that needs to interact with other low-level linux-based software however, C is probably the most efficient fit.

Rust (and maybe Go) do seem like very good long-term replacements for C, but imho it's too early to say that. Until there's a "full stack" of software (OS to user-space/desktop), you still kinda need to know C if you want to be able to understand how your whole computer works.