Why can't there be a universal religion that encompasses the good aspects of all religions?

According to Osho, a single 'universal religion' is impossible because human beings are profoundly diverse in body, temperament, and needs; any fixed creed suits only a few and imprisons the rest. Unity should be in love and fraternity, not uniform belief. Preserving many paths keeps humanity's spiritual richness alive; imposing one reduces life to spiritual poverty.