This isn't meant to invalidate what you're saying, but this whole thread reads like a parody to me. 1000 services all making requests to Zanzibar, and this oreo keto thing.
You could apply to S3, RDS, BigTable, Spanner, Firestore, etc. I feel like engineer orthodoxy (monoliths vs microservices, every monolith I've seen accesses a remotely DB and every microservice tends to access a DB which are themselves monoliths), no "god" services tend to break down for a lot of these important high scale stateful facilities.
