Within the same data center, a network call doesn't need to have significant performance overhead; it can be on the order of a read from main memory. Still over

Within the same data center, a network call doesn't need to have significant performance overhead; it can be on the order of a read from main memory. Still overhead, but for many SLOs it's irrelevant. The inherent cost of microservices is conceptual and organizational complexity, not runtime performance (though you can certainly build slow microservices, you can also build slow monoliths).