True. I missed that. With 10-20 years the general point still stands though. There should be quite a few movie blurays out there that are close to the end of their life.

According to this site the average lifespan of the cheapest type of bluray is 5-10 years. So a personal backup with makemkv (and maybe handbrake) might not be a bad idea.

Viable business idea in Germany.