Why was the Reconquista successful?

The term "successful" when referring to the Reconquista must be considered through the lens of how it relates to the initial goal of the Christian kingdoms who fought the roughly 770-year war to remove the Muslim influence from the Iberian Peninsula around Spain and Portugal.

Invariably, a war that lasts several centuries will see a large deal of bloodshed, victories, and defeats on both sides. However, because the Christian kingdoms who partook in the fighting ultimately largely saw the nearly complete removal of the Muslim Moors from the Iberian Peninsula at the end of the Reconquista, then one could consider the fighting successful for these kingdoms. After the conclusion of the Reconquista, Jews and Muslims who remained in Spain were forced to convert to Christianity. Those who refused to do so were forced to leave the country.