Due to a 400 error, I lost my post, so pardon me if I'll be short.
Yes, any internet site can disappear any time. See what happened in Strasbourg: a fire physically destroyed a bunch of servers, effectively erasing from existence millions of web sites:
https://www.reuters.com/article/us-france-ovh-fire-idUSKBN2B20NU
Bobo, if your concern is about keeping an alternate download solution for accessing the video encodes, then Torrent is just not an option. We should rely on online services of some kind, most likely a paid cloud service. A free alternative would be to use those multiple site uploaders that store a file on 50+ different sites at the same time. Then we would need to make a crawler that keeps track of deleted links, in which case re-uploads the files... It would be quite some work, but it would make any file download constantly available for free.
If instead your worry is about having a way of keeping backups, yeah Torrent may help, but only if there is at least one person keeping local backup of all video encodes, which would be about 600 GB, not counting mkv files and YouTube encodes. Anyone can do that if you have some bucks to spare for buying an extra memory storage.