One of the major problems that I see with old entries is that the material KYM is citing no longer exists. This is not a major problem with most references, but with videos it is almost critical; being the source of so many memes, the loss of an embedded video from an article deals it a mortal blow.
I suggest that we make it common practice for entry mods and prolific entry editors to create independent YouTube channels and reupload content that we intend to embed, whether it is dead or not, to prevent this loss from occurring. Furthermore, it should be the task of one intrepid volunteer to peruse the most popular old entries, especially the confirmed entries, and hunt down all of the missing videos from them as well.
I have pioneered this practice in this entry, creating a new YouTube channel where I intend to upload all videos in future articles that I work on.
The advantage to this is, of course, KYM entries can no longer be tampered with by rogue YouTube users who decide to spontaneously delete their videos. Of course the owner of the new channel could do this but, being invested in KYM, would be less likely to do so. In addition, we can tag them on YouTube as 'unlisted' which makes them far less likely to be removed for copyright strikes.
As an added bonus for anybody willing to go this far, we can also use this opportunity to trim down the videos in a video editing software before uploading, cutting out the unnecessary parts of the content to get straight to the point that the entry is trying to make.