Netflix & Spotify are aggregators, they own the consumer and distribution. Acquisition of movies costs either royalties to a studio or cost to produce the movie (actor salaries, etc.) Royalties are probably negotiated and the aggregator has leverage in negotiations because they own the consumer and distribution to them.
Insurance owns the patient, but the patient doesn't necessarily get to choose the medication. Their condition plus the doctor's prescription dictates what medication they can use. You're also not allowed to shop around for doctors who will prescribe what you ask for. Pharmacies own the distribution of medication. Drug companies need to recoup the massive R&D costs of developing drugs and thus are granted 20 year patents. This is somewhat similar to studios producing content and the copyrights afforded to those studios.
Not sure how to put all of this together but I think a big difference is that the consumer doesn't have discretion like they do in the Netflix/Spotify space. Maybe a good parallel would be Friends/Garth Brooks. If I want to watch Friends, I have to use Netflix or if I want to listen to Garth, I have to use Amazon Music. But despite the fact that I enjoy Garth's music, I can live without it or I can get it through other means (youtube, buying an album direct from a studio-owned distribution channel, etc.) People literally cannot live without some of these medications so consumer discretion is removed there.
Also, consumers don't have the ability to self-diagnose and self-prescribe. There are also no other distribution channels for medication. All of it must come through a pharmacy. There is no distribution done by the owner of the consumer(insurance companies), although PBMs may be a similar model?
Maybe somebody else could help me fill in the gaps with how the aggregator model is different from the pharmaceutical model or identify mistakes in my assumptions.