I remember hearing this somewhere when i was in high school, but can only recall them saying it was because of the training of massive numbers of paratroopers somewhere (im assuming Soviet), and how they had many more weapons being made every day.
The Soviets were indeed the first to utilize the concept of paratroopers, however most of their operations were limited with the majority of their paratroopers being used as regular infantry. That being said.... It depends on what angle one approaches this from, as this is one of those questions that never gets a straight answer, because even though it deserves one, it can't have one. Lets approach this from the view of validating your question. When Hitler went to war in 1939, he (as has been generally accepted) did not imagine the British and French would declare war for the poles (consider that Poland as a country existed for under 20 years at that point.) Even though the British and French did have obligations to defend Poland in the event of war, Hitler did not believe they would (Munich, Anschluss and the blatant violation of Versailles had shown them as weak.) One can argue that without the Soviet Union, it would have been a monumental task (it still was) to defeat Germany. At the start of the war, Hitler had signed a non aggression pact with the USSR, which would have kept Stalin out of a war he knew he wasn't ready to fight (its arguable that the USSR would not be ready for war until the mid 1940s.) Now that we have set the conditions as they existed in 1939, no the war was not lost the moment it began and until 1941, the world would have disagreed with this statement and here is why; the Germans had defeated the French (who had what most consider the best army in Europe at that point) and had the British with their backs against the wall with u-boats sinking British merchant vessels at an alarming rate. If you want to point to a single event that certainly ensured the defeat of Nazi Germany, you have two. The first being June 22nd 1941, which is when the Germans invade the USSR and December 11th 1941 when Hitler declares war on the United States. Those are two concrete days that certainly ENSURED Hitler would lose the war.
In his massive tome A World at Arms, the historian Gerhard Weinberg noted that after reading the memoirs of German generals. there was a common refrain of "if only the Führer had listened to me..." Weinberg sarcastically quipped that these memoirists should have added "the war would have lasted another six months, and then the Americans would have dropped an atomic bomb on Berlin."
Bearing aside the issues of the actual decisiveness of the nuclear weapons and whether or not the US could have brought them to bear on Germany, Weinberg's sarcastic comment has a lot of truth to it. The odds against a German victory were quite long and grew immeasurably shorter when the US entered the war. Germany simply lacked the resources to crush its opponents in the material-intensive war it found itself fighting. Barbarossa is a case in point. Germany invaded the Soviet Union in ideal conditions: it had achieved strategic surprise, the Red Army was out of position and still suffering the after-effects of the Purges, Germany quickly established air superiority, and the German armies possessed an operational cohesiveness from earlier campaigns. Despite winning truly massive victories in the various cauldron battles in 1941, the German armies could never completely destroy Soviet fighting power. German armies soon found themselves at the end of an increasingly strained logistical system facing a still-intact Red Army. Although German operational effectiveness meant Germany retained a degree of initiative in 1942, Soviet production numbers had began to outstrip German production in war material. In short, Germany could not win this war despite its impressive early victories.
The best sources for the macro-picture are Richard Overy's Why the Allies Won, Williamson Murray and Allen Millett's A War to Be Won and Adam Tooze's Wages of Destruction for the specific shortcomings of the German wartime economy.
This is most likely a reference to the economic realities of Nazi Germany and their inability to fight a long, sustained war against the Allies. There are several older threads discussing the economics question in detail:
What was Nazi Germany's economy like before WW2? Were they prepared/preparing for a large war?
How stable was the Nazi economy? Would it have collapsed without war as some claim?
Where/how did Nazi Germany get access to enough oil to fuel the war?