We use Kubernetes for our cloud database platform, which we are extending to new environments. It's been quite successful. We were able to port from AWS to GCP in a matter of weeks. We don't try to share tenants within a single Kubernetes cluster.

With that experience in mind, the storage section of the article is a hand-wave. Kubernetes is a major platform for high performance databases themselves. Saying that Kubernetes developers should "use databases" is not a very plausible answer in this case.

Object storage is not a panacea either. It does not exist equally in all locations and building caches to make it work efficiently in low-latency apps is a non-trivial exercise. (Like years of implementation work by PhDs if you want something good.) Locally attached NVMe SSD is still the winner for a lot of applications. It needs to be first class in Kubernetes and it needs to be easy to allocate pods that offer it. Applications can deal with resilience through app-level replication. Databases have been doing it for years.