So if/when Spotify ceases to exist, you lose everything. Even then, they can just decide to remove whatever music you liked “because” and you now lost access to it. In a few decades when people will want to listen to the old songs they used to like on “the Spotify”, they won’t find them anywhere.

It’s already happening for some movies.

EDIT: A friend just told me he did in fact cache some popular local albums on Spotify, and they just removed them. So those albums were accessible on Spotify at some point, but are not anymore.