Hello! I believe I'm one of the "manifested" security experts you're hinting at :)
Good security doesn't demand perfection, that's why security is both prevention and preparedness. The response from our admin was in every way beyond what you'd expect from many other orgs: prompt response (on the order of minutes), full audit of activity for the credential (none found), and full public disclosure ahead of the security researcher's report.
> JFrog also discovered multiple malicious package exploits later.
If you're referencing malicious packages on PyPI then yes! We want to keep PyPI freely open to all to use, and that has negative knock-on effects. Turns out that exploiting public good code repositories is quite popular, but I maintain that the impact is quite low and that our ability to respond to these sorts of attacks is also very good due to our network of security engineers and volunteers who are triaging their reports. Thanks to the work of Mike Fiedler (quarantining packages, API for reporting malicious packages, better UI for triagers) our ability to respond to malicious packages will become even better.
> Now we get a Github centric new buzzword that could be replaced by trusted SHA256 sums.
In a way, this feature is what you're describing but is easier to automate (therefore: good for you as a user) and is more likely to be correct because every attestation is verified by PyPI before it's made available to others (which is also good for users). The focus on GitHub Actions is because this is where many Python projects publish from, there is little incentive to create a feature that no one will use.
> Python is also big on business speak like SBOM.
Indeed, there is legislation in many places that will require SBOMs for all software placed in their markets so there is plenty of interest in these standards. I'm working on this myself to try to do the most we can for users while minimizing the impact this will have on upstream open source project maintainers.