No, they keep more money by making the artist pay for everything. If you're an artist, any cost the label has to cover (including the million dollars in that oh-so-sought-after 'million dollar contract') is essentially a loan to the artist. If you don't pay that money back, it comes out of your royalties. On top of that, you don't actually hold copyright to your songs. Until very recently, copyright reverted back to the songwriter after 35 years, but a change in the law means that the label will now hold the copyright forever. Fun, innit?
Something like 80% of artists never even make back their advance; the superhits get the rock star lifestyle and everyone else spends their lives in debt.
I've ranted on this subject before, but Alan Cross actually did a show on it and is much more articulate on the subject than I'm capable of being. The transcript is
here, at the bottome of the list (Why Performers Hate Their Labels.)