OK, so I mostly listen to classical music, but here's a thought.

I have heard some of Eminems' music, and it occurs to me that other traditionally 'White' genres such as Folk, Country or Heavy Metal would be radically unsuited to the themes, emotions and events he explores. Whether by accident or design, Eminem chose the only music genre that fitted what he wants to say.

As to the relative merit of his work, I am not competent to judge.