> Centralized logging? There is nothing to centralized.

It's still useful to have the various services, background jobs, system events, etc. in one indexed place which can also manage retention and alerting. And ideally in a place reachable even if the main service goes down. I've got centralised logging on a small homelab server with a few services on it and it's worth the effort.

> Load balancing? In practice most people for most work don’t use it because of actually outgrowing hardware, but because they have to provision to shared hardware without exclusivity.

Depending on how much you lose in case of downtime, you may want at least 2x of hardware for redundancy and that means some kind of fancy routing (whether it's LB, shared IP, or something else)

> Secrets management? There are no secrets to be constantly distributed to various machines on a network.

Typically businesses grow to more than one service. For example I've got a slack webhook in 3 services in a small company and I want to update it in one place. (+ many other credentials)

> Caching? Distributed systems create latency that doesn’t need to exist at all

This doesn't solve the need for caching results of larger operations. It doesn't matter how much latency you have or not, you still don't want that rarely-changing 1sec long query to run on every request. Caching is rarely only about network latency.