[Spivak]

This doesn't ring true for me at all and I've dealt with the dreaded omni-rails stack (or worse the dreaded tomcat springboot stack). Monoliths are far far easier to scale because you have one throat to choke and performance patches / elimination of n+1's spread across the whole app. Also in a monolith unit tests have the power of integration tests in a microservice world. I can actually be sure the boundaries between components behave as I expect and fail loudly if they change in a manner that breaks me. And the last thing in the world I ever want to do for scaling purposes is stick a network call/serialization step between two pieces of my own app because that's a bottleneck waiting to happen.

It feels like a lot of people reach for microservices when they should be reaching for sharding and/or moving to reads to replicas (which you can finally do in Rails thank god).