He obviously wouldn't get away with sampling Kanye's voice and selling it that way. There are already laws regarding AI art established in Japan that prevent you blatantly copying a persons style and making profit with it. Sampling and sourcing isn't so simple that you can easily get around copyright laws, especially if you are making a profit with it. If we're talking about that specific example just crediting Kanye isn't enough, he would need to negotiate and pay Kanye if he was going to sell it for profit. Maybe 70 years after Kanyes death people can start doing that freely - assuming no new laws are established by then.
As for talented ghost writers using AI, sure they deserve it don't they? They deserve it more than some pretty face who can barely sing, doesn't write their own music, doesn't write their own lyrics - getting all the attention and money. But they still have the issue of being able to market what they are selling and it's harder marketing something that doesn't exist, how would concerts work etc.