> Critically, there must be time for someone to review

By who? No one at npm is reviewing anything. "Someone" is doing a lot of work here.

Linux distributions have trusted maintainers who are responsible for their packages. People who cared enough to figure out PGP and set up an actual web of trust. That's where the verification happens. All these programming language package managers have nothing of the sort. PyPI, Rubygems, crates, npm, it doesn't matter. I can just make an account and push whatever I want.

These package managers are like this because that's what developers actually want. They don't want to deal with Linux distribution maintainers in order to get their software into the official repositories. They want to just run $packager push and have it out there with zero friction.