analysing a source-only-based distro (one where the compiler is required as a dependency) should make the importance of the compiler(s) clearer.
source-only distros include macports, gentoo, and so on.
source-only distros include macports, gentoo, and so on.
The graphs I'm traversing are the build-time dependency graph of all packages. I could also traverse run-time dependency graphs, but then I'd need to actually build all the things, because those are not known up-front unlike Gentoo and Macports.
The reason the toolchain is missing is because it is an "implicit input" as opposed to a "normal" input, so it's invisible/transparent to the query I'm making.