Art almost always takes a back seat in the mainstream. Criticizing rap as being "inartistic" as if it's somehow the exception to the rule is silly. It's not like Hinder and James Blunt represent the apex of artistic expression either. Look at your less mainstream stuff: El P, Del Tha Funky Homosapien, MC Abdominal, Busdriver, Gangstarr, Consequence, M.I.A. Hell even in the mainstream: Kanye, Lupe, Lil Wayne, T.I., The Roots, Outkast, k-os (in Canada), Dizzee Rascal (in the UK), Nas, Common, Jay-Z, Eminem, D-12, Jadakiss, CRS, The Clipse and even A Tribe Called Quest, who I believe are working on another album. Those names are all off the top of my head and if called upon, I could probably think of countless others. And the other stuff... whatever. I mean, it may not read like Shakespearean poetry or anything but it's catchy, and that's really what it's made for. It's the mainstream; every genre has its inexplicable successes.