> This simply doesn't work.

I think it works, and quite well even. Defaults matter, a lot, and Rust and its stdlib do a phenomenal job at choosing really good ones, compared to many other languages. Cargo's defaults maybe not so much, but oh well.

In C, sloppy programmers will generally create crashy and insecure code, which can then be fixed and hardened later.

In Rust, sloppy programmers will generally create slower and bloated code, which can then be optimized and minimized later. That's still bad, but for many people it seems like a better trade-off for a starting point.