Because rust is paying the price to compile everything fromch scratch on a release build, you can pay a little extra to turn on link time optimization and turn of parallelism on release builds and absolutely nothing gets compiled in that you don't use, and nothing gets repeated. Also enabling symbols to be stripped can take something with tokio, clap, serde, nalgebra (matrix stuff) and still be 2-5Mb binary. That is still huge to me because I'm old, but you can get it smaller if you want to recompile std along with your other dependencies.