(I'm talking proper festival headliners, and proper massive festivals (i.e. Glasto etc.), so don't some round here with your million dead/Standon Calling nonsense...)
I put it to you, that there is only one rock/indie band who fits his bill: Muse. What's happened to the modern day stadium band? Look at the headliners this year; they're all, with the exception of Muse, nostalgia-based headliners, or not headliner material:
U2 (nostalgia) then Gorrilaz: Fail
Stevie WOnder: Nostalgia
Arcade Fire: Fail
Blink 182: Fail
Eminem: Yes but not rock/indie
Jay Z: not rock/indie
Strokes: Close but probably fail
Other headliners of recent include REM (nostalgia), Blur (nostalgia), Oasis (nostlagia), Metallica (nostalgia). I guess you could make an argument for Green Day and RHCP, but only just.
This is a really badly written post, but i'm in a rush - hopefully you get my point. It's because there are so few viable headliner options that the likes of KOL and Kasabian get headline slots. More 'adventurous' festival organisers are looking further afield, hence Jay Z, Stevie Wonder, and apparently Prince next year for glasto.
Tell me who you think is a proper large festival headliner please.
ps i've just remembered coldplay but i'm not going to edit the above so include as appropriate