not to mention that "forever" with online streaming services tends to mean, "until licenses change" or the company changes hands and they decide to invoke the clause in the ToS you agreed to that says that you dont own and aren't entitled to the thing you paid for.

See recently, Crunchyroll Funimation acquisition. People had bought blu-ray copies at extra cost for a digital copy which was honored by CR and retracted after the merger where they promptly deleted the media that these people owned and paid full price for individually.