Why hasn't Allah (God) punished Salman Rushdie yet?

Salman Rushdie has written Satanic Verses in 1988. He has maligned Prophet Mohammed therefore he has done great sin. Muslims have condemned his Knighthood. I personally think he should not have been Knighted.It has been 19 years since he has written the Satanic Verses. Why has not Allah (God) punished or killed Mr Rushdie?