Completely off-topic, but k8s actually removes a lot of the vendor lock-in. Imagine having to migrate a k8s based app from AWS to Azure vs a pure AWS-based setup, provisioned with cloudformation. Sure it'll involve some work, but I know what I'd pick. I've personally ran workloads originally intended to be deployed on GKE on on-prem openshift clusters with very few changes, other than indeed the mentioned ingress stuff.

That was also the initial goals of k8s - make it universal so it's adopted as a standard by everyone else to make yourself competitive against the AWS juggernaut. And it worked.