There are other OSes and affected companies beyond the ones who were chosen to receive advance warning.
Imagine how it would work out in your airbag analogy if only Toyota and GM knew, and they withheld information for months while they worked on their own fixes, meanwhile the public remains in danger and other automakers have no chance to implement their own recall plans.
Can you mention which OS didn't get early enough warning? I'm sure there is some niche ones which may miss out but they are usually not the target of hacking either. And many of the derivative Linux distributions don't do active kernel development and just compile the stock kernel or derive from Red Hat, Ubuntu or others. The more people that are informed early, the more likely it will leak out early.
Imagine how it would work out in your airbag analogy if only Toyota and GM knew, and they withheld information for months while they worked on their own fixes, meanwhile the public remains in danger and other automakers have no chance to implement their own recall plans.