The ancient Romans made their circenses a centerpiece of public policy, along with free bread (panem -- also the name of the nation ruled by the "Capitol" in the movie). But they found that the spectacle of merely feeding people to lions, with no chance to win, became less popular than the gladiatorial contests, and that the gladiators wouldn't put on a good show unless they had a chance.

Video explains why people/governments behave in the manner which they do.