Why do you keep listening and more importantly why do you care?
Making threads about how garbage Eminem's music isn't going to stop him from making music and I'm sure the same people who talk about how garbage the music is, how nobody no longer listens to Eminem, how he never was somethigmng they liked listening to, etc. will still show up to discuss his new music. It really is the dictionary definition of insanity. You can control whether or not you listen to Eminem, so I don't understand the need for him to quit when you could simply quit listening to him and discussing him.