The typical C project has far fewer dependencies than the typical Rust project. Those dependencies are usually individually larger and either maintained by OS maintainers or there is a copy of the code that is built for the project and is readily available for audit. Those copies can't change without direct action.
Its less trouble to setup static analysis, address sanitizer, and similar tools for a C project than it would be to manage local copies of thousands of dependencies for a Rust project.
There's a bunch of threads going on simultaneously on HN now about how people often misuse AI by applying rules of thumb learned from doing things as a professional to what they prompt the AI to do, rather than just asking it directly for what you want. This is one of those cases. Many of the rules of thumb of professional programming no longer hold under the radically different economics of AI-driven development.
Its not even close to free in either $, your own personal time, or calendar time.