Yes, but Netflix has the option to not provide those streams to Comcast customers if it's not economically viable for them. As it stands, most Comcast customers

Yes, but Netflix has the option to not provide those streams to Comcast customers if it's not economically viable for them. As it stands, most Comcast customers only request 4k streams because Netflix defaults to the highest bitrate. Basically, by changing a default setting, Netflix pushes bandwidth and creates a tragedy of the commons situation.