If anything, this is the reason you use pull-through proxies. Your proxy will hold the version you depend on, regardless of upstream drama. Keep your proxy backed up and you'll be able to use those dependencies until the end of time, or you finally decide to migrate to an alternative.
If your package system allows this switch to another one, like, right now.
NPM, Cargo, etc. don't allow this (they "unlist" versions, but they don't "remove" them, i.e. you can't search for them, but they are still there).
I'd say the likelihood is about 50% you have a NPM package in your dependencies right now that pulls some binary or whatever from a random S3 bucket during installation.
And that's among the reasons people have started to commit their node_modules folders.
It has the neat side-effect of making people take a closer look at all the crap their pulling in too.
NPM no longer allows this.