YouTube videos degrade in quality over time too, as they reencode from one codec du jour to the next.

Heck, even Google drive pulled that stunt where they stopped storing photos in original resolution.

Point being, none of these companies exist primarily to archive your content - they exist to monetise it.

If you want to safeguard your content in original quality, then you need to either put it on a cloud storage that you are PAYING for, or keept it on your own hardware.