What was the reason of the Trojan War?

The Hittite sources showed that during 1300's B.CE. a hegemonial fight between two great powers, the Myceneans and Hittites, was waged over islands and coast of the Aegean and Anatolia. The Achaians, an allied army, made more than one campaign to conquer Troy. These campaigns seem to be the background history of Homer's Iliad. Some Achaian leaders even declared this region as a "promised land" and it played a great role in their interests. In the Bronze Age, as it was in 3000, also in 2000 B.C.E, the metals like copper and gold were coming from the Balkans, from the northern Black Sea area and the Caucasus. Especially tin was distributed over long distances. For this sea or land transport, they always had to enter Çanakkale Boğazı (Dardanelles). Troy became a very important trade center, since it was located strategically on controlling the entrance of the Dardanelles, between Mediterranian and Marmara Sea. In other words, the Trojan Wars were fight over money and power, and not for a woman called Helen. Even if we'd accept that the Trojan War started because of Prince Paris kidnapping of Queen Helen of Sparta, there remains the wealth as real cause: Helen brings her personal treasures to Troy. According to Homer, the Achaians attacked Troy both to get back Helen and the treasures.