Measures like this also aren't meant to be "final solutions" either, but stop-gaps. Slowing the spread can still be helpful when a large scale attack like this does occur. But I'm also not entirely sure how much that weighs against potentially slowing the discovery as well.
Ultimately this is still a repository problem and not a package manager one. These are merely band-aids. The responsibility lies with npm (the repository) to implement proper solutions here.
> The responsibility lies with
And I agree that if everyone did this, it would slow down finding issues in new releases. Not really sure what to say to that... aside from the selfish idea that if I do it, but most other people don't, it won't affect me.
It would not solve for a bad actor gaining trust over years, then contributing seemingly innocent code that contains an exploitable bug with enough plausible deniability to remain on the team after it is patched.