If npm stops being the go-to solution, another one will take its place, naturaly adopted by the community, following the path of least resistance. Centralized or not. It does not really matter. What does matter is the code that's being downloaded. Modules dependencies management is an old problem, countless of tools have tackled.
Is the node and front projects architectures that dependent on npm ? It's a little coupled but not that coupled ? The dependency management still require a little brain power from dev teams, or does it really fully relie on the package managers ?