Dug more into Zcash exploit and think the blast radius is much lower than what I understood on the show.
It's not infinite supply mint - it's infinite supply within Orchard (a specific shielded pool).
That represents ~25% of total circulating (estimated) and that is the max possible amount that can be counterfeit and removed from the Orchard pool.
This is why people are speaking confidently about the exploit having not happened - the flows associated to Orchard would look weird if someone got free ZEC within it and mass exported. If they were doing it consciously before to match inflows, surely they'd do it more heavily now that the gig is up.
The next upgrade coming down the pipe will implement a new pool with better soundness that people can migrate too and if everyone is able to migrate you can be fairly certain the exploit was never used - but it is NOT explicit proof that it was never used. You can only infer.