Over the decade, we have seen Hip Hop and Pop music dominating the music charts. I do listen to current Hip Hop and Pop music and i do like some of them but having grown up both as a kid in the 1980s and as a teenager in the 1990s, i do have a soft spot for Rock music. I would certainly like to see Rock back as a force on the mainstream charts.
The last great period when Rock had a strong presence in the mainstream music charts was in the 80s (glam metal, arena rock) and early 90s to mid 90s (grunge, alternative rock). The early 2000s did see some good rock bands on the mainstream charts like Korn, Saliva, Slipknot, Fuel and Puddle of Mudd.
While i am sure Rock will survive into the future, Will it be able regain the huge popularity it once had or even maintain a presence on the mainstream music charts against the likes of Nicki Minaj, Jay Z and Taylor Swift.
Are we going to see mainstream Rock evolve into something like the Folk Rock of Mumford & Sons, the Pop Rock of OneRepublic or the Emo Rock of Jimmy Eat World.
Or is the future of mainstream Rock is to be more like Nickelback or more like Foo Fighters?
The fact that you consider Slipknot to be good rock music is telling
Who cares about charts these days? Music has become fast food.. easily obtained, quickly consumed and forgotten even faster.
What is popular today will be forgotten in a year. Good rockers still fill stadiums easily and the top acts are still widely popular.
As with all music genres there is a huge variety in styles and as someone else said here your view is a bit US centric because the rest of the world is not so focused exclusively on R&B/Rap/Hip Hop music.