The catalyst is the shift towards software transparency: both the radically increased adoption of open source and source-available software, and the radically improved capabilities of reversing and decompilation tools. It has been over a decade since any ordinary off-the-shelf closed-source software was meaningfully obscured from serious adversaries.
This has been playing out in slow motion ever since BinDiff: you can't patch software without disclosing vulnerabilities. We've been operating in a state of denial about this, because there was some domain expertise involved in becoming a practitioner for whom patches were transparently vulnerability disclosures. But AIs have vaporized the pretense.
It is now the case that any time something gets merged into mainline Linux, several different organizations are feeding the diffs through LLM prompts aggressively evaluating whether they fix a vulnerability and generating exploit guidance. That will be the case for most major open source projects (nginx, OpenSSL, Postgres, &c) sooner rather than later.
The norms of coordinated disclosure are not calibrated for this environment. They really haven't been for the last decade.
I'm weirdly comfortable with this, because I think coordinated disclosure norms have always been blinkered, based on the unquestioned premise that delaying disclosure for the operational convenience of system administrators is a good thing. There are reasons to question that premise! The delay also keeps information out of the hands of system operators who have options other than applying patches.