Germany and Japan were never going to be able to compete with a United States that was going to just keep producing Tanks, Boats, guns, airplanes, munitions, etc with no interruption in supply.
War is as much about logistics and supply.
Start running out of stuff at critical moments and you lose important ground.
We were always going to have the ability and will to bomb everything into oblivion with no interruption in supplies and very good logistics or at least logistics that would eventually meet demand.
Germany was only going to lose that battle and Japan never stood a chance, as they have nothing.
No metals, Oil & Gas, gunpowder, etc. They were an overly ambitious island nation, who could only gain supplies for logistics by taking over peoples.
Germany had the same problem but, the ability to simply annex a few more yards of real estate.
They were never, ever, ever going to be able to keep up a pace sufficient to attrite us and ultimately the war ended on Atrrition, as most do.
Run out of supplies, you run out of men.
Finally, the war was about avarice for the Axis and about liberty for American and the Allies.
The Axis could only conscript men, who were motivated by bayonets at their back.
America had men volunteering in droves to help their fellow man and were willing to kill for their liberation and then simply go home.
One set of values has a more enduring and lasting motivation than the other...
With endless supplies one set of values was going to win over another no matter what.
“America had men volunteering in droves to help their fellow man and were willing to kill for their liberation and then simply go home.”
By winter ‘44, manpower was already becoming a critical issue for American forces, and training was being cut back to get more men out faster. Conscription standards were also lowered.
In addition, despite already being at war for 2 years, the casualty lists were only then becoming huge, and this was already creating unrest. That unrest played a large part in the decision to use the nukes. The idea of a million+ casualties invading Japan would have created a real political crisis at home.
There has been much written about this over the years.