The thing I noticed is that they are not using any other AWS services. No S3, Elasticache, DynamoDB, etc. They are just running applications and databases.
This will not be the case with many people using cloud and a migration to bare metal will be much harder. Each of those services needs an equivalent to be deployed and managed and it's features might be up to what the AWS equivalent has.
Even the stuff that they are moving (databases, load balancers, etc) is significant operational overhead. In AWS database fail-over is an option you tick. Self hosting has whole books written about how to do database high availability.
This will not be the case with many people using cloud and a migration to bare metal will be much harder. Each of those services needs an equivalent to be deployed and managed and it's features might be up to what the AWS equivalent has.
Even the stuff that they are moving (databases, load balancers, etc) is significant operational overhead. In AWS database fail-over is an option you tick. Self hosting has whole books written about how to do database high availability.