1. The Soviet Union did have a ton of natural resources. However, Russia had not developed as fast as Western Europe did, and so the Soviets were trying to catch up, technologically. Also, the communist system of the USSR, as well as the chaos of the 1914-1922 period (war and revolution), set the USSR back in many ways.
However, while Soviet equipment has generally been less advanced than Western equipment, its simplicity meant that more could be built, and they were often tougher and more reliable. Consider the Soviet T-34 tank and its German counterpart, the Panther - the T-34 was much simpler and cruder, but the Panther was extremely expensive to build, maintain, and repair, and early on had a number of reliability problems. Consequently, even though the German tank was "better," the Russians could build many, many more T-34's that were good enough to do the job and which could be used all over the front.
2. The USSR reorganized its military continually throughout its history. Reorganization during World War II began in earnest after the disasters of 1941, and by the end of the war the Soviet Army was the biggest and most powerful in the world (although it did not have many reserves to draw on to replace losses and Soviet industry and air power would not have been able to compete with Western industry and air power in a long war with the West).
I'd place the best Soviet generals on an equal or better footing as any in the world in 1945 - German generals especially get overrated because they wrote self-serving memoirs to cover up their errors and complicity with Nazi crimes - blaming everything, from war crimes to strategic errors, on Hitler and the Nazi political leadership - that became popular in the West, while Russian generals didn't get much credit in the West for Cold War political reasons. As an American, I wouldn't want to have to had fought Rokossovsky, Koniev, Chuikov, Tolbukhin, or Zhukov, even given Bradley or Patton or Hodges or Devers (and certainly not MacArthur or Clark).