Man-of-Leisure Cable providers usually fit between 4-8 HD video streams in a QAM depending on the content and if the streams are MPEG2 or 4. Talking heads can compress much more than a movie with a lot of explosions or gradients or sports with a lot of movement. They need much higher bitrates than AV1 or HVEC for the same resolution.
HEVC or AV1 at the same resolutions and lower bitrate could double that video stream count and look better, yet it still doesn’t solve all the various distribution issues streaming providers commonly have as pointed out in the original post of this discussion, especially during big live events.

HVEC or AV1 does allow the cable providers to provide better quality video using less bandwidth on their own streaming platforms compared to their QAM distribution, though.