I really like the idea of a package/dependency manager. It just seems that when ever I am reading a tutorial and they want to import something that is not standard they say write this in to your TOMOL not cargo install it. Like when reading python docs they all say to use pip or something. Sorry it just seems that Cargo is somewhat overlooked or is it just my perception?
You are confusing cargo and crates.io.
Cargo is the program doing all the downloading of dependencies, crates.io is the official registry (but there are ways to host your own for private crates, e.g. kellnr), Rust is just the compiler and does not do any downloading of anything. For completeness sake, rustup is the program you can use to install cargo, rust and some other tooling and data files.