One was a billionaire business honcho who created one of the most identifiable brands in the world. Another was one of the greatest Computer Scientists who ever lived.
As great as Ritchie was, he never stood a chance. There are a number of relevant reasons to bash Jobs but to say that he overshadowed Ritchie's death is one of the more stupid ones. Dennis Ritchie was mourned by those who respected and adored him regardless. His death would have only received a minuscule amount of increased attention than it did probably had it not coincided with Jobs' death.
Moreover, his death probably received even greater attention due to the increased effort people have put in since to highlight him.