also, one key aspect is. There are may be individuals out there that can do this.
however, usually code is written by multiple people. (and i would also count your future self as another person).
that collaboration on the same code base requires automatic tests, otherwise the next person will break the code in non-obvious ways.
It's painful to write because writing software that is memory safe is not easy. Rust makes it insanely easy in comparison to the "old way" of doing it (hacking together a C program then having to patch security holes every release, never being certain that your code is actually memory safe).
> Can I not write a well designed and correct program in C? Of course I can.
Of course you can. All it takes is a separate formal proofing process, countless hours of static analysis and many more months of fixing security bugs. Good thing that's so much simpler than Rust's static analysis which runs on every compilation and mathematically proves that its memory model was not violated.
I think if we have learned one thing in the history of C programs, it's that this sentiment that "a sufficiently smart programmer can write safe C code" is quite harmful. While technically true, I don't think I've ever met such an individual and I doubt one exists.