Blu-Ray discs can carry mandatory software updates that change the functionality of playback devices, add “protections” against “piracy, and could potentially revoke licenses of content on other discs.

Media companies are prepared to screw you over regardless of wether or not you but content from them. I do believe in paying for content, but I don’t trust any modern distribution to last, so I have a couple backups of all the media I’ve ever purchased. And for formats that make it difficult to back up, I sail the seven seas.