Can anyone give me one good reason a programming language should bother with dependency management?
Nix has the right idea, but the execution is spotty and poorly documented IMO. Not to mention they have a serious problem with package naming, which strikes me as a glaring issue.
When a programming language tries to ignore dependency management, like Go and Python did for too long, an ecosystem will soon spring up of a bunch of informal third-party tools for managing dependencies, all of which are only partially compatible with each other. It works better when the designers of a programming language include dependency management in the design and promote one official way to do it, like C# or Rust.
(I say this even though in general I prefer Go and Python to C# and Rust - you have to respect what the different tools do better.)
Start standardizing language agnostic interface, thus fixing the compatibility issue and I only see this as a good thing.
Disclaimers: I work for AWS, but not on the AWS CLI; AppFS is my own personal project
A programming language with the ability to dispatch on version could be very interesting, and possibly allow for safer upgrades on a per function basis.
Still it feels like this should be part of an interface between a PL and some other set of packaging options. A convention for where to place libraries (with versions) like /lib is basically the solution. But I guess the various communities don't really want to get into a turf war, so maybe it's /lib/ruby and /lib/python in addition to the rest?