While you are correct the majority of Google services internally are Stubby-based, it isn't correct to say gRPC is not utilized inside Google. Cloud and external APIs are an obvious use case but also internal stuff that are also used in open source world use gRPC even when deployed internally. TensorFlow etc comes to mind...

So "not used much" at Google scale probably justifies 40 people.

> I think most people assume that gRPC is what Google is built on, therefore it must be good.

Dropbox[1], Netflix[2], Apple[3], Microsoft[4], Slack[5], and lots more are all either built on, or heavily use, and/or contribute to various pieces of gRPC and the ecosystem around it.

[1]: https://dropbox.tech/infrastructure/courier-dropbox-migratio...

[2]: https://netflixtechblog.com/practical-api-design-at-netflix-...

[3]: https://github.com/grpc/grpc-swift

[4]: https://learn.microsoft.com/en-us/aspnet/core/grpc/?view=asp...

[5]: https://slack.engineering/how-big-technical-changes-happen-a...