Although the wicked can prosper, they never can quite find happiness in their ways. The "natural man" inside them tells them that unrighteous living will bring happiness, and that promise continually drives their actions. Fleeting pleasures and temporary highs may come from wicked behavior, but lasting peace and constant joy aren't ever attained in that way. To counter this obvious lack of fulfillment, Satan convinces the wicked that they already have all the happiness they can have, or that happiness is pleasure and nothing else, or that the happiness will come after more wicked acts. The wicked live in a state of perpetual misery as a result of believing this perpetual deception.
God put us here not for the purpose of giving everyone riches and prestige, but so we can have the opportunity to attain the real, lasting happiness that He has attained. Like any good Father, he wants His children to have what he has, but He won't force it on us. It is up to us to choose either eternal happiness or eternal misery. Riches and prosperity are nice and great to have, but they are not the source of happiness, nor are they the purpose of life.