That's missing some of the bigger picture. One of the reasons streaming 4k content is at a lower bitrate is because it has to deal with network hiccups and fit

That's missing some of the bigger picture. One of the reasons streaming 4k content is at a lower bitrate is because it has to deal with network hiccups and fit inside the buffer of most playback devices. A computer or phone has plenty of room, but streaming 4K content to a TV or chromecast/roku/firestick/etc. does not. Faster bandwidth means keeping the bucket full more reliably.