Why would you patch a security vuln in a later version? Should be patched in all versions.. that's what semver is for.
Who is 'you' here? All of the npm package maintainers?
Yes, if they all just backport security patches we'll be fine. No, people are not going to just.
Ah yes the incredibly common practice of... checks notes backporting security packages in node packages.
Semver doesn't help if you just declare all older versions EOL.
What you're looking for are Debian stable packages. :p
A patch updates is a newer version, and they are just as likely to be compromised by supply chain attacks as minor or major updates.