I don't really understand what you mean by this or how it relates to what I said.

I certainly wasn't suggesting that you can vertically scale a service to handle unlimited traffic on a single instance.

The point is that if you have stateless services, where the resources being consumed per request are mainly CPU and network bandwidth, then "scaling independently" is not a useful thing to do. You can just scale everything instead of artificially restricting which instances can handle which kinds of requests.

This is obviously incorrect conclusion because scaling stateful services is considerably harder than stateless and typical design involves heavy caching (which technically is state just not durable state)