People definitely have strong opinions on submodules, but it is nowhere near so one-sides: a ton of people hate them, and a ton of people swear by them. FWIW, a

People definitely have strong opinions on submodules, but it is nowhere near so one-sides: a ton of people hate them, and a ton of people swear by them. FWIW, all of the Rust libraries I use are available as git repositories. With many other package managers, I can tell them "don't use the upstream copy from the package repo: use the copy I have in this folder" in a trivial manner. I thereby don't really want "automation" around either downloading the code for me to mirror or for the submodules I want: I want to set it up and then configure it so it is all "honored"... and I could totally see the feature you talking about somehow only working one way (with automatic copies) instead of being flexible.