No, I don't think it is. Early itunes was a media player and music store I could use to catalog my own music as well as license theirs. Spotify is a streaming music service with a free ads based model or paid monthly subscription to get access to most commercially released music. How is that anything like Pitch vs PowerPoint templates?
I was just referring to the 'Subscription service vs One-time purchase' model. If you want to make a single presentation in a year, perhaps, not considering any differences, you are better of buying templates on Themeforest. But the convenience, cost-effectiveness of such a service, i can certainly see value