That's the thing from the customer IT perspective. When your Microsoft-administered systems go down at the same time as the rest of the world, nobody blames the CTO or any of the sysadmins. The global outage becomes an acknowledgement that it's not their fault, so nobody in the company actually gets blamed, and nobody gives them a hard time.
It might not result in more uptime, but it does mean that any downtime doesn't get pinned on them.