Yes, Linda, these are all factors that helped determine the duration of the war, but it was industry, primarily American industry and Russian manpower that were by far the deciding factors.
But there were also silly things that the allies did to prolong the war. For one, Churchill was a wonderful allied cheerleader but a terrible strategist in both WWI and II. He pushed for the Italian campaign, a terrible idea. The rugged mountains of Italy gave the Germans perfect defensive positions to defend and grind up allied forces.
The so call soft underbelly of Europe was really the Rhone Valley of Southern France as it was later proven to be. It was a grand highway for American tanks. The perfect play would have been to make an invasion feint toward Rome but then suddenly veer into Southern France a few weeks prior to the Normandy operation. That is not just hindsight thinking, that’s what most of the generals preferred, but Churchill was obsessed by the political symbolism of capturing Rome — the hard way one might add, all the way up from the heel of Italy.