It's wild to me that MVS didn't get picked up everywhere else for their next-gen package managers. Picking up "fixes" automatically turned out to be a boondoggle, if not a security risk. There's no reason we need to write a SAT solver just to manage our library dependencies.

Not really, it's not about downloading. If it only works offline given the appropriate files, that's fine too. But a package manager needs to actually install and uninstall packages!

I could see a case being made that programming language functions, especially in ruby where everything is message passing, forms a package manager. A method might actually want to guarantee that when it sends a message foo that the code receiving it remains fixed.

Being able to declare dependencies that granular might actually be great for doing refactors and upgrades. Maybe we accepted too easily that dependencies for a project are global.