Why do they do this? It seems every update the Spotify client becomes less and less useful.

Money, most likely. Removing or obfuscating user choice allows them to push you towards content that they curate themselves, presumably to pay fewer royalties or something similar. I kind of ignored it until they started removing dislike options, at some point not even having hulu bundled will stop me from switching to a competitor.

or, you know, maintenance cost in hours/developer.