They are not mainstream radio. They are not even 'standard' anything. Feel like all opinions of them stem from their Brothers album which is the only one to get mainstream attention of any kind, and is not an accurate representation of their body of work. -Six Albums-, and it doesn't seem like anyone who gives their opinion of the band has ever listened to the other work and has just brushed them off.
I could be wrong, on that. But, I have noticed a very obvious progression from one album to the next, where nothing sounds the same while still retaining their style.
To me, they have roots in blues, but they are so much more. Some experimental styles, some hip-hop beats. More just classic, kick your teeth in, rock and roll that still doesn't sound exactly like anything I've heard before. Again, it has roots. But I've never heard this particular sound before. Their style is pushing the envelope because in the past 10 years, it's a rare thing for a band to use an older sound and do it well enough to garner massive attention.
I am not lying when I say that I have -never- heard a song of theirs on the radio. Ever. I'm sure they play them somewhere, but even after Brothers, they are not even that mainstream.
I get that Radiohead did something fantastic. They popularized a 'new' sound and tried something before anyone else really caught on. But all music can't be defined by if it 'broke new ground' or not.