The issue: developer pulled their package off NPM, which many packages depended on.
The solution: keep all packages in NPM. If the software is open sourced, we can legally continue to redistribute the software even though author may not want us to.
Ecosystems with this issue: Python, Ruby, Go (google it)
Ecosystems without this issue: Maven, Haskell
I respect someone wanting to pull embarrassing or private data, or even just out of spite. In that case the package can be made undiscoverable, but still accessible from direct download.
Non relevant issues: laziness; micro vs standard vs kitchen sink libraries; package security; package quality; package maintainer coordination; ... but the color of the bike shed is just so interesting.