I'm not sure how this could work for a free service at scale. Treating a free youtube account as a video storage service is a really bad idea. I think the issue is that this works for most people most of the time, so we come to expect it.

There are alternative paid options (vimeo, dropbox, S3) that should work fine.

This is also a big problem with gmail, hotmail, and a thousand other email providers. Most people assume their data is permanent and safe in a free email account. That's probably true 99.99% of the time, but it's not guaranteed. If your data is important, you should really pay someone to host it, or back it up yourself.