Reading the NPM blog today - that's not really a problem in NPM.
Reclaiming a module name requires a breaking version for any new code, so it shouldn't be an issue there.
It's still an issue for any developers who use '>' instead of '~' or 'x'. That's quite a few.
Twitter API clients are required to delete all copies of tweet contents when a tweet is yanked, or Twitter will revoke API access, which might bring your production systems to a deserved halt.
Yes but they won't accidentally pull a malicious version of the tweet pretending to be the original. They'll just stop working
That is an unacceptable outcome for production systems.