I'm sure he's referring to the RDS outages, and the multi-AZ RDS's that didnt fail over properly. Many of them didnt fail over properly because the issues was EBS...where all the RDS live...
Just like many have said on here plenty of times before this outage. Dont just rely on multi-AZ to be your DR while in AWS. Leverage the other regions.
The regions are completely separate datacenters with no shared components. You have to be pretty dense to think that AZ's are completely independent of each other, considering all the services that are shared between AZ's. The AZ's may be separate datacenters, but they have tons of shared tech, which ends up being the main SPOF.
Ah the argument of iron over cloud. It would cose significantly more to buy the hardware to be redundant enough to avoid a situation like today. If these large sites still aren't buying their own hardware that seems go along with that thinking.
Have scheduled tasks to create AMIs of your infrastructure. Create scripts or redeploy by hand into another zone when an extended issue has occurred, or deploy and leave powered down as part of a 'DR' plan or something.
Just like many have said on here plenty of times before this outage. Dont just rely on multi-AZ to be your DR while in AWS. Leverage the other regions.