It seems they value developer productivity and innovation over machine performance. I find this enlightening.
With containers on top of VMs, you now have to manage which containers run on which VMs (and the cloud provider worries about physical boxes), with a pure container solution you just spawn containers (and the cloud provider worries about physical boxes)
They might not be deploying containers on VMs on bare metal because they want to, but because they /have/ to.
Not on AWS.
If you are running a webapp and a database with a known workload, not so much.
That one piece of lazy coding held back Javascript on their platform for years, and I'd argue that it as the most significant cause of their browser's market share plummeting (or at last tied with lack of adblockers).