I think the answer is yes and no depending on your needs. I don't have a lot of experience with the Kubernetes NetworkPolicy which does support selector based allow/block of communication between pods, but I believe it does not encrypt the traffic itself (although you could always do so on top of the network layer). It also is constrained to only controlling communications within Kubernetes and requires an actual controller to implement the networking. Consul Connect does use a sidecar proxy for intra cluster communication, but in addition to just the authorization it also does a mutual TLS and can allow that secure communication to endpoints outside the cluster. It now occupies a space very similar to Istio: https://www.consul.io/intro/vs/istio.html
For development environments we are running MSSQL (yes that MSSQL, unclustered though as there is no SAN emulation of course), Elasticsearch, Mongo, Kafka, Zookeeper, Redis, Memcached, all in Kubernetes (mostly as Pet Sets) and looking to possibly do this in prod once we are happy with it. The story for state in Kubernetes is improving rapidly.
MySQL and PHP both released in 1995 or so, there was a lot of movement in the "late 90's" so it really depends on where in there they are actually talking about.
I don't see how it follows that they are admitting something by shrugging their shoulders. But what this is missing is that there are technical reasons for flat design, namely performance and power usage, that are critical on mobile devices.
Disclaimer: I work for HC but not on Consul