Wouldn’t writing/reading to/from Kafka sort of be orthogonal to micro services?

I say this not to argue one way of another for services, just to say that I think your example is just Kafka, or more generally event driven architecture. One thing that defines services is a request/response messaging pattern. In other words a service makes a request and then they wait for a response, like http. What you’re talking about resembles a service because the producer/consumer are separate processes, but they don’t really have much else in common with services, due to a different messaging pattern.