For some real-world examples of this issue, you can look at how the only reason we have any of the early BBC news reels and TV shows is because of copies recorded by people on their TVs. The BBC reused the tapes that they recorded on for new programming to save money on buying tapes. When they started to think about the preservation of news and shows like Dr. Who, they had to turn to the general public and ask them to donate any recordings that they might have made.

It's estimated that more than 50% of all video games are lost forever because companies didn't care to save a master copy, and this has already come back to bite some of these companies in the ass with the recent trend of remakes and remasters. There was a recent remake of one of the GTA games from the early 2000s that was very poorly received, and it turned out that the company who worked on it only had the mobile phone port of the game to work with because Rockstar hadn't bothered to keep a master copy of the game. There was another recent remake of a game that was very obviously done using a pirated copy of the game as the source, because they hadn't even bothered to remove the cracker's logo from the game.

With examples like that and Sony recently removing thousands of people's access to music and movies that they bought on basically a whim, it's pretty clear that preservation efforts will be done in spite of companies rather than helped by them. And so that means copies of things will be one random harddrive failure of some single person on the internet away from disappearing forever.