Why did the Muslims fail to conquer Europe after the Battle of the Martyrs' Plain and the Siege of Vienna, and will they return to conquer it in the future?

The Battle of Tours was a decisive one, considered by European historians a disaster for Europe, as it missed the opportunity for Paris to become a civilized center like Cordoba. The continuation of the conquest was prevented by the disunity among Muslims and the abundance of conflicts, while the Christians united and began the Reconquista. The return of Islamic conquest is an امر كائن (a destined matter) by the permission of Allah, and it is the duty of Muslims to achieve the factors of victory by returning to the religion, acting in obedience to the Lord of the Worlds, and preparing material strength.