[cshenton]

Probably because it's pretty bleeding edge.

Google Cloud Endpoints, which released earlier in the year, allows you to write a gRPC server, and offers the HTTP proxy as part of the service.

The ecosystem still isn't quite there though. It could be easier to just write a thin webserver that just points at services over tcp (using something like ZeroMQ) rather than writing a service with gRPC from the ground up.