The problem is that some content creators have already passed away (and others will pass away by then), and their videos will likely be deleted forever.
Hopefully the deletion will not affect videos with thousands of views, even if the account is lost.
Monuments erode away and memories of those enshrined are lost time as well, nothing lasts forever.
That may be, but I assume for videos that had some viewership base, there may be a consideration. E. g. if a video was viewed 20 million times, it may be worth more than one that was viewed only 5 times.