That is what diminishes the artist and his song. The artist is now hermetically sealed. The publishing company got him his deal and they expect to profit from his songs. So what if he is a better singer than a songwriter; let's put him in a room with a real songwriter. Something great is bound to come...except very often nothing great comes out of such contrived match-ups. Nobody knows where a great song comes from, and that's why so many writers credit the Lord as a co-writer (though I notice they never offer Him half the writer's royalties) when they come up with a real gem.