I know Roon wants deep integration with music streaming but if Spotify doesn’t allow their API to be integrate into Roon, Roon should provide an alternative way of playing back Spotify. Spotify is the world biggest music streaming providers with more 100 million paying subscribers. Providing a platform for playing back help to increase Roon subscribers rate. I think this is a simple maths.
Not many music streaming providers want to give their APIs and provided if they already can support hardware playback, it too can be done on the Roon. I’ve switch from Tidal to Spotify because of the huge music database and intrusive interface. In the end of day, it is contents really matters not so much of the quality if it can be improved over time.