The whole thing is a shit show and really I'm rather more behind OpenBSD's approach.
Edit just to expand on this as someone deleted a post ....
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It's slightly more complicated than the prisoner's dilemma. The prisoner's dilemma doesn't account for a large facet of the problem which is being discussed here. If all the good parties participate and coordinate then we're better off. The problem is there are outlying circumstances which means that not everyone will be included:
1. If someone kicks someone out (OpenBSD) on political whim playing CYA, they no longer benefit.
2. If a party is not let in, they no longer benefit.
3. If someone is unaware of it, they don't benefit.
This turns it into a security monopoly where the big vendors get exclusive rights to embargo and exclude smaller vendors and control the disclosure process on their own schedule.
The first thing the people outside of the club find is they wake up on Monday morning and have to clear up a shitstorm of monumental proportions with less resources than the monopolised vendors who've had time to deal with it.
Then there's the assumption that the monopolised vendors are trustworthy which is 100% impossible to validate and therefore invalid.