Man, you don't need to use service mesh just because you use k8s. Istio is a very advanced component that 99% of users don't need.

So if you are going to compare with a managed solution, compare with something equivalent. Take a bare managed cluster and add a single Deployment to it, it will be no more complex than ECS, while giving you much better developer ergonomics.

99% of users don't need kubernetes. Just deploy to heroku, and you'll have a much better developer experience.

My wallet says otherwise

You mean operators?

(genuine tone, not rhetorical)

Sure, an operator is likely to use a wide array of APIs.

But, to reiterate, everything uses APIs. The *betavX APIs are of course likely to be deprecated and replaced with stable APIs after a few versions.