I absolutely agree. For all of its tactical and operational successes, Barbarossa, the German invasion of the Soviet Union, was a strategic failure. Its goals of destroying the Soviet armed forces before they could retreat into the interior and to bring about the collapse of the USSR were both unsuccessful and with the advantage of hindsight unobtainable. Germany had grossly underestimated the size of the Soviet armed forces and their mobilization potential, meaning the object of destroying the Red Army before it could retreat to the interior was an impossible task as massive forces were being raised in the interior even as those close to the border were destroyed. These victories didn’t come cheap for the Germans either, unlike the case in the defeat of France. David Stahel wrote a series of books dissecting the fighting from Barbarossa (Operation Barbarossa and Germany’s Defeat in the East) to the Soviet counteroffensive at Moscow (Retreat from Moscow: A New History of Germany’s Winter Campaign, 1941-1942). From Operation Typhoon: Hitler’s March on Moscow, October 1941:
On 22 June 1941 the Red Army numbered 5,373,000
men; by 31 August, in spite of its losses, it had grown to 6,889,000;
and by 31 December 1941 the army had reached an estimated eight
million men.
While the Red Army was growing in size the Ostheer was
shrinking. Although there was access to reinforcements from the
German Replacement Army, these reserves were very limited and their
transportation to the front could not keep pace with the rate of loss. By
the start of August Army Group Centre had lost some 74,500 men, but
had received only 23,000 replacements. With 85 per cent of German
men aged between 20 and 30 already in the Wehrmacht by the summer
of 1941, and those remaining outside either ineligible for health reasons
or judged too important to the war economy, the reserve manpower
pool was indeed small. The commander of the German Replacement
Army, Colonel-General Fritz Fromm, outlined the limitations to Halder
in a discussion on 20 May 1941. After deducting a share of men to act
as a reserve for the Luftwaffe (90,000 men), Fromm determined that the
Ostheer would have access to 385,000 replacements. With surprising
candour Halder noted that 275,000 casualties were expected in the
initial border battles, with a further 200,000 expected in September.
Thus, by Halder’s own figures the Replacement Army would not suffice
for the demands of the campaign through to the end of September and
nothing at all would remain if the war dragged on longer. In the event,
by the end of September, the Ostheer had lost even more than Halder
estimated. Between 22 June and 30 September some 551,039 men were
recorded as casualties, a figure far exceeding the Replacement Army’s
capacity, plunging the Ostheer into a rapid and irreversible decline.
Logistically the infeasibility of Barbarossa is evident by the situation at the launch of Operation Typhoon, the German push to take Moscow after a two month pause by Army Group Center which had outstripped its supply lines and during which its forces were turned south to aid in bringing about the encirclement of Kiev. Amazingly, even with two months to improve their supply situation and build up stockpiles, there was not enough fuel on hand in October when it was launched to actually reach Moscow. From the same source:
If Typhoon was following an altogether classic course, so too
were the operational problems now emerging. Before Guderian could
even think about driving on to Tula he first needed to address his near absent fuel reserves. Langermann-Erlancamp’s 4th Panzer Division was
momentarily unopposed on the road to Tula, but unable to exploit its
advantage for lack of fuel. On 5 October Guderian requested 500 cubic
metres of fuel be flown to an airfield near Orel, but at best Kesselring
could only manage about 70 to 100 cubic metres on 6 October.
Likewise, Schweppenberg’s XXIV Panzer Corps was also pleading
for more fuel, which led to another demand on Kesselring’s already
overextended transport capacity. As Guderian acknowledged, the
availability of fuel for Operation Typhoon was essential; ‘the future
extent of our movements was ultimately dependent on this’.
Nor was Panzer Group 2 the exception. Hoepner’s advance on Viaz’ma was
already causing problems for Vietinghoff’s XXXXVI Panzer Corps
because fuel shortages combined with bad roads were slowing all
movement. Even worse, after being halted by Soviet counterattacks
on 4 October, Hoth’s Panzer Group 3 could still not advance on
5 October because fuel stocks had been totally exhausted. Kesselring
was again requested to fly in urgent deliveries in order to restart the
attack. Astonishingly, in the midst of such basic shortages and with
the offensive only days old, Wagner, the army quartermaster-general,
wrote in a letter on 5 October:
“Operational goals are being set that earlier would have made our
hair stand on end. Eastward of Moscow! Then I estimate that the
war will be mostly over, and perhaps there really will be a collapse
of the [Soviet] system … I am constantly astounded at the Führer’s
military judgement. He intervenes in the course of operations,
one could say decisively, and up until now he has always acted
correctly.”
Such blind devotion and professional incompetence was by no means
limited to Wagner within the OKH. Indeed, given Wagner’s many
shortcomings and failed promises, his survival in the post of
quartermaster-general only confirmed the support he, and his judgements, often enjoyed. Importantly Wagner was an enthusiast for all
manner of Nazi ideals, including the power of individual ‘will’, which
asserted the power of the spiritual over the tangible. Following this line
of Nazi mythology, German troops, regardless of the supply situation,
could conquer Moscow so long as they remained determined to do so.
The folly of such belief should have been apparent during Operation
Barbarossa, but the absence of a learning curve within the German
high command doomed Operation Typhoon to repeat many of the
previous mistakes.
The parallels between the Nazi belief that ‘will’ could overcome any material problems and the Imperial Japanese belief that ‘spirit’ could do the same are obvious.
Importantly for the sake of the premise of the OP, all of this was accomplished before lend-lease from the US had anything but the tiniest effect, the first lend-lease protocol from the US to the USSR wasn’t signed until October 7, 1941. During the Cold War the USSR downplayed lend-lease as if it was entirely unimportant, which clearly wasn’t the case. It certainly was of great help in allowing the ultimate speed of Soviet advances against Germany later in the war. Without lend-lease the war would certainly have dragged on longer and may have led to something of an incredibly bloody protracted stalemate in the East, but Germany was very unlikely to actually defeat the USSR even without lend-lease being a factor.