Nice writeup, Austin!
I have been surprised by how many people discount the value of the portability provided by containers and Kubernetes. It reminds me of the time when everybody lost their mind over XML some years ago, and we were all doing XML situps because it was good for us.
The Kubernetes developer experience is very nice. The GKE experience is even more refined.
The one thing that is holding GKE/GCP back, as far as I am concerned, is the lack of built-in support for PostgreSQL within Cloud SQL. Yes, one can run the container within the cluster, as you have clearly shown. This is awesome in development. For production, I would greatly prefer to outsource the the operational aspects of running PostgreSQL to the cloud provider.
Have a look at the following to see what I am getting at:
This is brilliant work, but there are 14 containers in that diagram.
The day that Google Cloud SQL offers native support for PostgreSQL will be a very big day for GCP.