These compromises are usually caught within hours by security researchers performing automated scanning of all published packages.

Except that exhaustively scanning for badness is provably impossible.

It's inevitable that a false negative will slip through one day, and when that happens, it will compromise everyone who installs it, no matter if on day one or day eight.

The idea isn't to comprehensively make malicious code impossible - the idea is to make it difficult to sneak in. If the NSA wants to spend 500 billion$ to compromise an NPM package, there's very little we can do. But if waiting 3 days for security scans catch even 10% of malicious packages, that 's 10% fewer incidents everyone else has to deal with. And now people pwning maintainers must be much more sophisticated so their attacks are entirely undetected for that period.

Makes sense.

I just hope that the companies who currently perform security scans for free/for exposure have a sustainable business model. Once such a company gains reputation, there's diminishing returns in headlines currency.