I agree almost completely with this statement. The vast resources of the Allied powers, and of the US and the Soviet Union in particular, were the most important factor in allowing them to win the war. However, there were at least some other factors that mattered.
The resources of the Allies made the most difference in the outcome of this war. The United States had a huge land mass with lots of natural resources. It also had easy access to more resources in the rest of the Americas. None of this could be touched in any important ways by the enemy. The Soviet Union had a huge land area with natural resources and a large population as well. These factors allowed the Allies to produce huge amounts of weaponry and, in the case of the USSR, to absorb a full-scale German invasion. These were their main reasons for being able to win the war.
However, there were other factors. One such factor was the poor strategy of the Axis, in particular Germany. Hitler made some egregious errors, not least of which was the invasion of the Soviet Union. Another factor was the weakness and impetuosity of Italy and Mussolini. This was a real liability for the Axis.
Overall, though, I do agree very much with the idea that it was resources that allowed the Allies to win.