I agree the OA is a bit disingenuous about acknowledging the risk of deployments, but the four metrics you came up with also don't tell the whole story. Of course there will be more breakage after a deployment, the real question isn't whether that's true or not, it's whether subsequent deployments will becomes even more risky by withholding earlier deployments.
Not all risks are equivelent. There is a reason planned outages are scheduled for ~2AM local time not ~2PM local time. Plenty of companies have dealt with 2h windows where if the site is down they fail. Some have even been down during that time period and ended up laying off everyone.
