Microservices exist because of the limitations of a single human brain in being able to wrangle with that much logic at a time.

It is perfectly conceivable that an alien species with different brain characteristics would draw their microservice boundaries at very different points, possibly varying by a whole order of magnitude in either direction.

I don't agree that there are organizational causes even though that's oft repeated as one of the main reasons. I have never seen a one-to-one relationship of microservices and teams irl. Most teams own many services and some services get touched by many teams. In big companies, there are also microservices with zero owners.