Must own a Toyota. The connection for the camera to be powered on already exists on the models listed. It can come pre-installed from the factory or can be added after purchase through the service department. It's not a standard connector (like USB). Every automaker uses their own types of connectors for various components.

It's already a thing. You are correct.

Toyota 100% offers them on a handful of models. Reasonably priced too. https://www.toyota.com/owners/dashcam