Nothing really disappears, the question is how strong the ecosystem is in ten years and how good the support for the code you write today. Rust will not go away but I doubt that the code written today still works without hassle or that all the 1000 crates it depends on still exist. That there are dark corners using C89 or K&R is not a weakness, it demonstrates how strong the C ecosystem is. If you write something in Zig or Rust now, you need to realize that in 10 years it might also be considered ugly legacy code, even if you think it is shiny modern code today. The question is then if it is as easy as using "gcc -std=c89" to work with it.
