Final answer:
1) Italian port cities like Venice and Genoa capitalized on the Crusades by facilitating trade between Europe and the Levant, establishing outposts, and profiting from weakened commercial rivals.
2) If the Crusades had not occurred, these cities might have faced a slower economic growth as they would have lacked the impetus to find direct trade routes and stimulate demand for Eastern goods.
Step-by-step explanation:
1) The Italian port cities such as Venice and Genoa had several advantages that enabled them to profit from the Crusades. Due to their strategic geographic locations, these cities were ideally situated to serve as intermediaries in the trade between Europe and the Levant.
The Crusades facilitated the establishment of lasting trade links with the East and weakened potential commercial rivals such as the Byzantine Empire. Furthermore, the Italian city-states secured concessions to establish mercantile outposts in key locations, boosting their economic prowess.
2) If the Crusades had never occurred, the economic trajectory of Italian port cities may have been considerably altered. Without the heightened demand for Eastern goods stimulated by the Crusades, the drive to establish direct trade routes may have been less urgent.
Consequently, the accelerated period of exploration and trade that followed the Crusades might have been postponed, dampening the economic growth these cities experienced during the late Middle Ages.