It’s not for everyone in that I agree with the point the author makes. But if you have multiple teams doing app development k8s can be really nice. We do data movement and ML services. AKS has proven great for our use.
You do however need some folks who know Kube & systems. If you don't have them, hire some but not just for kube. If you can't do that, then yeah, it's a real personel investment.
Once you start having mtiple teams doing more complex stuff, you either need teams that work well together, or some kind of entity to figure out how not to make a mess. Turning on rbac is a significant early step towards being a mature, scale-out capable team.
I have yet to see an org scale past these needs myself, but most of me & my colleagues experience is at smaller/medium sized orgs.