The simple fact that both the Germans and the Japanese were able to roll out new weapons and aircraft even to the end of the war shows something about the difficulty in beating a determined opponent.
Germany had many V weapons in development as well as new fighters and bombers and armor that were very advanced at the close of the war. The Germans continued to work on atomic weapons but had many set backs due to Allied intelligence and resistance efforts.
The Norwegians sinking a ferry containing heavy water, British Mosquito attacks on a test lab in the alps. American heavy bomber attacks on machinery factories all had a devastating effect.
In the movies, German Armor squeaks just as much as anyones, Anyone who has spent a few days around tanks and tracks, knows that they all creak and squeak.
If you really want to understand the amount of equipment and effort that America put into the war, read some of the books on the giants of american industry at the time. Henry J Kaiser (
http://en.wikipedia.org/wiki/Kaiser_Shipyards) was just one, read his biography and see what we had going here as ways to produce equipment. Understand that in FIVE days that's right FIVE DAYS, the SS Robert S Peary, a Liberty ship, a 440 foot, 13,000 ton ship was built in FIVE days. Look at the people behind North Carolina Shipbuilding Company, from river bank to one of the top production ship yards in the WORLD in less than three years.
A pretty good primer on the Marine building capacity is here...
http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/116liberty_victory_ships/116liberty_victory_ships.htm
Consider that Henry and Edsel Ford took aircraft production to incredible levels producing a B-24 every hour at the Willow Run factory. Everyday, 24 new bombers rolled off the line, at just one factory, of just one type.
Understand that the US was fighting two wars, against separate enemies, on fronts spread out over most of the world. We were building ships at a rate many car builders of the day would have found impressive. We took car makers and had them making tanks, airplanes and artillery. We produced enough food to feed two other nations and made sure their armies were fed as well. WE had one mine, (the Hull-Rust mine) that supplied ONE FOURTH of the Iron ore used by the US in WWII, in the process we dug a hole nearly 600 feet deep, a mile wide and 2 miles long.
The Germans built 1400 ME 262's in all variants, but because they were spread out all over germany for safety from production, because skilled pilots were not available, and because slave labor often did a poor job of construction, only about 300 or so reached combat units.
United states fighter production.
P51's 15,875
P47's 15,686.
P38's 10,037
Hellcat's 12,275
wildcat's 7,732
Corsairs 12,571
Airacobra 9,562
superCobra 3,303
P40's 13,738
Total 100,779 fighter aircraft,
This does not count light, medium, and heavy bombers (30,000 alone in B-24's and B-17's) , C 47 and C 46's. Catalina's, and other types.