Cameras use isochronous mode, which maxes out at less than half the theoretical max USB 2.0 bandwidth, and they use MJPEG compression on each frame rather than

Cameras use isochronous mode, which maxes out at less than half the theoretical max USB 2.0 bandwidth, and they use MJPEG compression on each frame rather than something like H.265 that can compress much more by leveraging P/B-frames.