>Unless you're someone who only had to work on a monolith deployed to a single box somewhere,

I think the point is that 90%+ of websites are fine with a few monoliths behind a load balancer. That set up can handle low thousands of requests per second in Rails/Django/etc. Maybe low 10 thousands with a more performant language.

And it's not just k8s. It's the whole microservice/SOA that comes with it. It ramps up the complexity of everything and is a constant time sink in my experience.