In my experience, profiling is hard and a lot of times doesn't show the issue. e.g. for unnamed goroutines it is hard to see which goroutine profiler is referring to. Or say if some code change increased CPU usage without increase in time/memory, it will affect the entire monolith performance. Yes a good maintainer could pinpoint the issue, but remember my premise was that it is low trust environment, and saying I think your code change increased CPU usage involves talking to managers and being in 2 meetings. And in microservice they would have to deal with their alerts to not miss the SLA.

> Microservices is just taking a monolith and moving the components into separate processes that communicate via RPC.

Microservice architecture divides the responsibility much more than that. They have separate redis cache, local cache, tests, and even likely has different DB etc.