I seem to recall reading that the HD variations may get removed leaving only 480p or lower for older unwatched videos.
The original upload would likely still be stored, but not available for viewing.
The original upload would likely still be stored, but not available for viewing.
If they really wanted to compress, take out every other frame, and regenerate those frames with a neural decoder. But I don't know why that would be worth the effort for a stable number of low res files either.