Because they don’t have a perfectly fine business model. They get squeezed hard by both the oligarchs of music publishing UMG, Sony Warner who negotiate the price for the music. And from the other side by the tech giants google and apple who can cross service subsidize their own streaming.There exists essentially no space for them to make any profit in streaming music. So they have to go other places.

The only reason they’ll probably exist for the foreseeable future is because the rights holders are able to use Spotify to have more negotiating power against Google and apple.