This seems like extremely acceptable collateral damage to me. Sectigo should already be working with their customers to reissue immediately since they are the ones who signed the dumb intermediates. Trust only matters if there’s accountability. If root CAs want to keep their trust, it’s on them to not sign things that are bad. That’s the responsibility that comes with the license to print money that being a root CA gives you.

If I’m an OS vendor I would have been putting them on notice days ago that their root was being dropped and they have X days to reissue certs and deliver a new root cert or otherwise they can just accept that they’re not qualified to be a root anymore.