The European Commission has fined Apple over €1.8 billion for abusing its dominant position on the market for the distribution of music streaming apps to iPhone and iPad users (‘iOS users') through its App Store. In particular, the Commission found that Apple applied restrictions on app developers preventing them from informing iOS users about alternative and cheaper music subscription services available outside of the app (‘anti-steering provisions'). This is illegal under EU antitrust rules.
Spotify should have handled their issues with the app store rules but just not making an IOS app. If the biggest music streaming service in the world didn't work with iPhones maybe Apple would have had to reconsider some things.
Conversely, not being on a platform with a very considerable amount of their current userbase could cost them massive amounts of subscribers, and possibly allow competitors to take their place.