Yes, very few wars have been won by the side with the least men and resources.
The reason the Union won the war is because it never lost the political will to fight. The only chance the Confederacy had, was to fight to a draw and make the Union decide the cost was too great and then seek a political decision. This was a possibility in the early stages of the war, but once battles such as Shiloh produced 25% casualties on both sides, the Union had to pursue the war, if only to justify the cost and losses. Lee's march into Pennsylvania was the last desperate attempt to press for peace terms which left the Confederacy intact.
As for Lee's sainted status, that is something of a mystery. He was a good officer and managed an incredible campaign under the worst of conditions. However, he led the Confederate Army to Gettysburg and into a battle which depended upon incompetence on the other side, for any chance of success. The Union forces did the obvious thing, which was to sit and wait for Lee to attack. It was a bold gamble and a dismal failure.