As long as DRM exists, it’s only worth renting, imo. “Buying” media with DRM is essentially an expensive long-term rental. It will last as long as the company decides to keep the servers up to support it.
(from wikipedia) Music on the iTunes Store was the original use case for the development of the FairPlay DRM scheme (such friendly naming!). It was apparently the SJ "Thoughts on Music" letter that started the end of DRM for purchased music, but my somewhat cynical opinion is that was also the point where streaming was becoming more plausible and streaming services complete undermine everything by explicitly removing the option to buy music.