Good point! It was not a given, but right now it seems like Reddit’s choices (and related events at Twitter/Meta) have been driving new platforms to emerge. I’m still incredibly suprised by the adoption of Lemmy and Kbin and especially the quaility and diversity of available apps for the platforms. It’s just really cool to see what people can do when they care about communitites of people coming together.
I don’t think Spotify supports uploading your own music files. It can indeed show local files, but i’m not aware of a upload mechanism such as YouTube Music has.