Zig is not safe, it's a C with a better templating system (comptime).

Ada, is not popular enough, is my guess. To be fair, writing everything in Ada Spark would make code way more secure, simply because you'd need to write your pre-condition, invariants and post-conditions upfront, and prove they hold, but no one seems to want to think about lifetimes, let alone think about programming in more mathematical terms.