There are several issues with protobuf that do not make it an option for adoption.

1. Data structure enforcement at the API layer is redundant with ORM. ORM creates the object that can be cached; protobuf objects are duplicates.
2. PLUS... the protobuf has to be created per each individual variation for ROLES (ie a USER role may use their principal to request data and only have a partial return wereas an ADMIN role may request by ID and have a complete return).
3. Even with Dynamic Messages, you are adding alot of duplication of the object, lack of checking/coordination between the two objects and DynamicMessages makes it as fast as a normal REST API.
4. If you are using ORM, you have to convert the protobuf object
5. If you are using a CACHE, you have to convert the cached object to a Dynamic message

…And you HAVE TO USE dynamicMessages to be compliant with OWASP api security guidelines.

These all slow down the overall response. And HTTP2 will support binary responses. So we can just wait til then.