> It's not physically possible to run post-mortems for issues at those rates.
Not at all, you merely move the goal post of at what layer the "root cause" actually could come from! At that speed, it's always something short and sweet, while when you actually want to long-term address things, you have to have time to even investigate organizational issues or whatever the actual problems stem from.
But you have half a day? "Post-mortem: Push X wasn't properly analyzed before deployment, in future more testing" and call it a day.
“A failure occurred. This was caused by something going wrong. Changes to operating guidelines have been instituted to ensure that things will not go wrong in the future unless we happen to do the same thing again.”