I don't recall their name, they were a guest on the Root Causes podcast discussing PQ topics, though your summary varies from what I was trying to express. It's not that RSA will be classically broken, but that novel attacks to reduce factoring times of RSA key like batch attacks have a statistically significant chance of being discovered, that "further" was not meant to imply "completely broken classically," but "weakened further using classical approaches". Sounded plausible to me, though that's not a thing I'm any kind of domain expert in.