Why does doing the right thing not always guarantee success?

Growing up your taught to follow the book. Like get food grades, respect others, work hard, aim for high paying job and marriage.. but the more you observe life there is so much corruption like in workforce there are this top people in corporate who are greedy and take all the advantages of promotions, bonuses, stocks and opportunities meanwhile rest of workers are only meant to work hard and fill their pockets. Sometimes I feel that people who take shortcuts and being selfish feels okay nowadays. I guess not everyone is destined to follow the book.