Job descriptions are usually something like: "As a Technical Evangelist, you will be the face of the platform and often the first contact our customers have with us, both online and in person."
Do tech evangelist roles really have the power to send things back to the product teams? They always seemed more like platform adoption/marketing people.
That's... not what technology evangelists do. Tech evangelists are the public face of a specific, often open-source, product/project. There are no tech evangelists for "all of Google". These are narrowly-defined roles, and they aren't empowered to be the public face of the company outside of that area.
Job descriptions are usually something like: "As a Technical Evangelist, you will be the face of the platform and often the first contact our customers have with us, both online and in person."
https://en.wikipedia.org/wiki/Technology_evangelist