Yes it was, but it was improving. FDR & Churchill were skeptical that the USSR would see 1943 and had a plan to carpet bomb the Baku oil fields in late 1942.
Stalingrad wasn't a miracle, it can be explained. On the German side, Hitler was increasingly running the Army in 1942, and he had mistakenly convinced himself that the Russian army was kaput as Operation Blue proceeded. This is because after the Kharkov '42 debacle in 5/42, Stalin started taking advice from his generals & retreated during Blue as the Russians had done with Napoleon. Hitler split his Army Group South, half to Stalingrad, half to the Caucausus, & got cut down on the Volga. Part of the reason why he forbade Paulus to escape the encirclement in late November is that the Germans still didn't know the Red Army was as strong as it indeed was. Thus, the window of opportunity quickly closed for Paulus in late November, because by the time the Germans figured out what they were dealing with, the encirlement had been solidified by the Russians.
At the micro level, Chuikov was hand picked to defend the city because he had been in Siberia during Barbarossa, and still had his spunk. He instilled it in his troops, who may have in poor shape in September as the city fight began, but had good morale. The German morale plummeted as they quickly got bogged down in the city, & saw the war wasn't over, and would have to endure a 2nd winter in Russia.
So, even though the Russians were taking 10 casualties for every German, at least 100,000 Russian troops crossed the river into the city from 9/12/42 - 11/19/42. Most of the Russian troops defending the city were fresh, adequately armed, supurbly entrenched, and defending their land. The German troops were veterans stuck in a war of attrition, knew they were the aggressor, and were in for a 2nd winter.
You have to remember that Germany was still fighting with one arm tied behind it's back pre-Stalingrad, because Hitler was wary of public support. Stalin had no such worries, & gave it his all.
Mid September was very touch & go for the Russians in Stalingrad, but after that, arms, equipment & men started flooding in. No miracle.
