It's a vendor pitch, so take it all with a nice grain of salt.
Protocol buffers have large problems in their own way. Just because Google produced them does not mean they are the right choice for any broader adoption than they already have.
I agree with the idea of schemas for API definition. JSON and XML are more transport-level, lacking major semantics that must be enforced in the software, Therefore, schemas need to be expressed with language bindings.
Protocol buffers have good traction here because of the investment that Google has made in IDL with multi-language bindings. There are other serialization formats as well with many language bindings, but investment in the IDL needs to be made. The OP is drafting off of Google.
So, yes to the thesis and no to one of the conclusions.
Protocol buffers have large problems in their own way. Just because Google produced them does not mean they are the right choice for any broader adoption than they already have.
See https://news.ycombinator.com/item?id=18188519 for example, and note that the the discussion on personal vs technical aspects has already happened.
I agree with the idea of schemas for API definition. JSON and XML are more transport-level, lacking major semantics that must be enforced in the software, Therefore, schemas need to be expressed with language bindings.
Protocol buffers have good traction here because of the investment that Google has made in IDL with multi-language bindings. There are other serialization formats as well with many language bindings, but investment in the IDL needs to be made. The OP is drafting off of Google.
So, yes to the thesis and no to one of the conclusions.