Don't have any issue with what you say, except for the first point, which I will address. On the other though, Germany was not prepared for a long war, although it was probably inevitable...there was no real purpose to the war, while there was a lot of German aggression, they tended to stumble into things, their strategy was largely directionless. For instance, there was no real intent to go into the Medit. other than propping up Italy; there was also no actual plan for beating the Soviet Union, simply an expectation that if they killed enough, and captured a couple of cities which were important in the german mindset then the Soviets would give in. Similarly, the germans declared war on the US, with no real plan. German armoured development kicked on after the invasion of the Soviet Union, when they came up against their 1940 vintage tanks - T34's and KV's...that caused a shock.
Regarding the first point, there was a significant disjoint between US industry, and the combat front, combined with a lack of depth. There was no real single doctrine for armoured combat, resulting in a mixmatch where tanks were to fight anything but other tanks, and enemy tanks were to be fought by 'tank destroyers'. While an original concept of the US armoured force called for something around 60 armoured divisions, they eventually only reached around 20, but had enough tank destroyers to equip (if they had been tanks) another 16 divisions (in the European theatre). Added to that, there was a swarm of 'GHQ' tank battalions, supposedly to supplement infantry divisions etc. The British weren't much better, with the concept of cruiser tanks and 'infantry' tanks, but at least that was roughly comparable with the use of 'main force' tanks and 'heavy' tank units in other forces.
Battle wise though, western strategic art was far behind what the Soviets were up to. While the Soviet art of war cost massive losses, they were losses that they could and did accept, in a battle doctrine that was intended to overwhelm and shatter opposing forces on a massive scale...the strength of their abilities in that regard was to be able to do so, repeatedly, putting each of the German army groups through the mincer one after the other, while both logistically and administratively supporting those massive forces, and actually increasing them. At the same time on the western front, the Brits and US were attempting to emulate the blitzkrieg 'single point' breakthrough model of 1940, which was well and truly past its' use by date...they then, in 1945, had to resort to a broad front offensive, although by that stage the germans were no longer what they once were.
The lend-lease program was voted the 11 march 1941. on the 14th of augustus they signed th e Atlantic chart. US were escorting shipping convoys to nations in war. Hitler gave orders to the u-boats to not fire on any circumstances on any american naval ship back then to avoid being forced in a war with US he didn't want but proposed in the same in time in july 1941 an offensive alliance to the Japs. He knew the naval battle was impossible to him and his u-boats and the colonies were everything to the war effort so he counted on the Japs to make the job. These orders were not respected, there was the USS Greer incident on 4 september 1941 and the HMS Broadwater being sunked on 18 october 1941. Then it continued with the USS Kearny on 17 october and USS Reuben James on 31 october 1941. All by wolf packed u-boats chasing the convoys. It didn't lead to any declaration of war. Pearl Harbor did the job cause there was there a clear intent to sink american naval forces and a few days later the entire Axis joined. All that was planned cause there was no possibility to win any war on the german side if the economy convoys from USA and british and french colonies were left untouched. The germany strategy was always to force quickly separate peaces. The whole bombing of english cities followed this logic as the rush to Moscow. It lead to the opposite effect though.
I wouldn't dare to speak about Soviets doctrine i don't know shit about that but afaik the Soviets were the perfect example of using people as meatshield... Not the US in that matter.
And i really don't know where you are going with this, we speak about 80 000 tanks losses on the Soviet side, not speaking about the personnal obivously... To me there is really nothing in there showing any "superiority".