Even if they were trustworthy, nothing lasts forever.
Does anyone seriously think Google Play Movies or whatever they call it is going to be around in 50 years? Audible? Spotify?
Unlikely.
I grew up with access to books that were printed before my parents were even born. I doubt your grandkids will be able to say the same. Not if you buy into DRM-infected ecosystems and vendor lock-in, anyway.
The only consolation is that pirates are always one step ahead. But I wouldn't want to count on that remaining true in 50 years either.