It's an old language. Some of the fundamental mistakes were just things that were common at the time and only look so bad in hindsight (e.g. strings, locales, nullable pointers, half the k&r standard library). That doesn't mean we can't and shouldn't do better where we can though.
C and C++ targeting WASM, despite all the security message of how great it is, memory locations inside of the same linear memory segment can still be corrupted, thus providing a way to influence the overall execution logic inside of the sandbox.
At time C was written, swapping in/out of memory measured in literal minutes & when fraction of second of execution time, including swapping in/out of memory, was more than several times the average yearly salary of the day (excluding sneaker net intervention)