They didn't create it though (At least that's the argument).
Very few artists make money through record sales, and this has always been true not just recently with Spotify.
Even in the '80s bands were starving but then people pointed to Guns and Roses as examples that made money from record sales. Record labels signed contracts with bands to record and press albums, they took 90% of the money and gave artists cash up front. Unless they were already Aerosmith, the deal wasn't great.
People bitching about Spotify taking most of the money, whilst it might be wrong, don't seem to know their history. If you want to support bands it has always been about seeing them live and buying merch.
Artists don't get good deals from Spotify because their labels are signing bad deals for them and it doesn't matter "if they made the music".