This is exactly it. It seems like every service is raising prices with no noticeable improvement to the service itself. Hell, this would be easier to swallow if Spotify was going to pay artists more. There doesn’t seem to be any benefit to anyone other than Spotify’s bottom line, which I assure you, is doing just fine.
I don’t know that I’d consider this “mildly” infuriating. Good on you for having any semblance of composure!