For instance, I don't regard one of our products that runs in three availability zones and has 3-4 instances per AZ as being "large scale". It is still a small system. And it doesn't run in multiple AZs for performance reasons but because we really need high availability.

We embedded discovery, failover and automatic cluster management in the server software itself. But it isn't really how we'd like to do it. But it is still less of a hassle than running K8S. (It also means that we can do that if you license our software to run it on-prem on pretty much most runtime environments, and that has its value, but again, this isn't functionality you want or should have to do yourself)