Sure, but that's not something you can fix at the ecosystem level, it requires effort from the package maintainers and/or researchers to backport these fixes to

Sure, but that's not something you can fix at the ecosystem level, it requires effort from the package maintainers and/or researchers to backport these fixes to older versions. And if the fix requires effort from the maintainers that is not actually very benefical to anyone (i.e. the vulnerability does not actually impose a security risk) then we are back to the question if it's really worth it. The effort has just been moved from the consumer to the library author.