> If you are using small crisp API boundaries to break up the system, "smart developer quirks" don't really matter very much

To me this is the upside of the microservices concept. Of course, true microservices take it way too far. But once you tell two teams they can only talk to each other with APIs and make them use tooling that properly defines what those are (schemas etc) .... all of a sudden they are forced to draw those boundaries well and then stick to them. And they get really conservative about changing them and think hard about what the definitions should be up front. It's sort of perversely sticking technical friction in at the points where you want there to be natural conservatism around change.