Paul wins because he recognizes that spice dependence is more powerful than formal sovereignty. The Emperor commands Sardaukar, the Great Houses possess armies, and the Guild controls interstellar transport, but all three systems require melange. Once Paul can credibly threaten the sandworm-spice cycle, the Guild refuses to move the Great Houses against him. Military victory becomes political supremacy because ecological knowledge supplies the final leverage.
His marriage to Irulan is strategic. It legitimizes his claim through the Corrino dynasty and prevents the defeated Emperor from offering her to a rival. Paul tells Chani that Irulan will receive his name but not his affection. Jessica's final observation distinguishes legal marriage from lived partnership, but it does not erase the cruelty of making both women instruments of dynastic settlement.
The ending is triumphant only at the surface. Paul has avenged his father, destroyed the Harkonnen leadership, taken Arrakis, and forced the throne to surrender. Yet the Fremen no longer follow merely a duke; they follow a messiah whose legend has accumulated beyond his control. His choices may shape the coming war, but his victory makes it nearly impossible to stop. Herbert ends where a simpler heroic narrative would celebrate because the consequence of the hero's success is the real subject of the series.