That problem solved, but plenty of other things hiding in that 'simple' setup of just 5 concepts.

Which is why you don't lose your SRE/OPS team just because you k8s.

I'd say that if you aren't big enough to have dedicated SRE then k8s is not for you. However, it really only takes 1 or 2 people to manage pretty large clusters with 100s or 1000s of deployments.

That's where my company currently finds itself.