What about the vulnerabilities that OpenBSD notice? Works both ways. And they have an active interest in such things and have discovered as much as any famous-for-five-minutes security researcher.
> [OpenBSD] have discovered as much as any famous-for-five-minutes security researcher
TL; DR OpenBSD acted rationally if they'd prefer to go it alone, which seems to be their culture. To their credit, it's worked pretty well so far. But you can't have your cake and eat it too. If they prefer a mad scramble after public disclosure, they'll get it. But they shouldn't get early notice from responsible researchers.