He answers their prayers provided they pray with sincerity and faith. People who say that their prayers are not answered are people who do not have much of a faith in God and who pray just like that on the off chance that He might after all help. By and large, the majority of devotees belong to this category only. They pray with a selfish motive. Materialism is their creed.
Worldly success is their goal.
They are not interested in the theory of rebirth or in the other world or in spiritual salvation. To the extent that God can help them in their material ambitious, well and good. These are the people who, when they get into trouble, when they are faced with difficulties which they find themselves unable to tackle with their own wit, turn to God out of sheer despair and helplessness. These are the people who, though not normally given to visiting temples and doing worship, will one day suddenly clean the Puja room and light lamps and buy flower-garlands to decorate the Deity. Once their prayers are answered, the lights in the Puja room will go out, and in the place of flower-garlands, cobwebs will gather.