Also, for cargo's usecase (mostly-reproducable builds, a space that rubygems also attempts to fill) system package managers are simply insufficient. Nix is the

Also, for cargo's usecase (mostly-reproducable builds, a space that rubygems also attempts to fill) system package managers are simply insufficient. Nix is the only one that comes close, and you A) can't remotely expect anyone to have that installed already B) have no control over the repository or toolchain