It is certainly not simple, and while there's a limit to what languages can do to assist correctness, C sets a particularly low bar, one that newer low-level languages like Zig and Rust can and do improve upon. Having said that, eliminating memory errors from C is not only doable in principle, but used in practice, so far more than new low-level languages (see, e.g. https://trust-in-soft.com/). It does take a fair deal of work, but for established codebases, the approach is cheaper, less risky and better established than new languages.