Bootstrapping of the rustc compiler from scratch is a very different experience than using the language as a user. Bootstrapping requires building a C++ mrustc proto-compiler, which is where the tons of flags are needed. The rustc compiler has a custom multi-stage build system to make it and its standard library built with itself, which multiplies the time it takes. It's designed to be consistent and optimized, since most users download a pre-built binary.

However, once you bootstrap it (or willing to trust someone who did), it's a breeze to build Rust projects with Cargo: `cargo build` just works with no extra flags for the majority of projects. The only finicky builds are ones that rely on C or C++ deps.