Idk I built a production system and ensured all data transfers, client to server and server to client were proto buf and it was a pain.
Technically, it sounds really good but the actual act of managing it is hell. That or I need a lot of practice to use them, at that point shouldn't I just use JSON and get on with my life.
What issues did you have? In my experience, most things that could be called painful with protobuf would be bigger pains with things like JSON.
Making changes to messages in a backwards-compatible way can be annoying, but JSON allowing you to shoot yourself in the foot will take more time and effort to fix when it's corrupting data in prod than protobuf giving you a compile error would.
I think the it-just-works nature and human readability for debugging JSON cannot be overstated. Most people and projects are content to just use JSON even if protos offer some advantages, if not only to save time and resources.
Whether the team saves times in the longer when using protos is a question in its own.