NEVER is a very long time.
Victor Davis Hanson's brilliant perspective is reflected rather fairly in "The Myth of the Nazi War Machine" link. I argue with none of it.
HOWEVER...
France was the #1 rated military in the world by a wide margin in 1940.
The Maginot Line was the most advance defensive system of the day.
France had More and Better tanks than Germany.
France's air force was very well equipped, and Germany lost as many planes in France as they lost in the battle of Britain.
YET...
France fell in weeks. Germany and France were technically at war for a year prior to the invasion.
No one on earth, including most of Germany's general staff, thought Germany was foolish enough to attack France.
It was shocking and horrifying.
THEN...
After the Blitz. Germany again did the unthinkable by invading the Soviet Union in June 1941.
YET...
October 41 through January 42 saw the Germans besieging Moscow.
They failed narrowly but many speculate that the fall of Moscow, and the possible capture of Stalin... who stayed in Moscow... might have brought the collapse of the Soviet Union.
Stalin commented that the Germans would have taken Moscow if they had one more narrow gauge locomotive.
If the Germans effectively consolidate their power at that point, they can out build the US and UK. We can bomb, but not invade. The T-34 tanks would have been a massive upgrade, and Russian aircraft production was actually good.
SO... No Normandy landing.
North Africa is very different. The Suez canal falls.
No oil problems for Germany.
You suddenly have a massive empire, both powerful and evil. And we still have Japan to fight starting December 7, 1941... significantly during siege of Moscow.
What was that again about NEVER?
Hitler, against all reason, declared war on the US. He didn't have to, and probably would have won, had he not. There was no reason for us to not just "go to war against Japan". Europe seemed lost anyway, and the Soviet Union was just as bad as Germany. Instead of exploiting this opportunity, Hitler squandered it.
Many in the UK wanted to "deal" with Hitler even with our alliance. How would that have played out if we decided to focus on Japan?
A year later, Operation Blue was on it's way to the Baku oil fields, and unwisely got sucked into house to house fighting in Stalingrad. We all know how that went. This was not the quality opportunity that Moscow presented, but stranger things had already happened in this war. Fortunately, Hitler's decision making led to the loss of 600k troops, the best of his mobile striking force. The Baku oil fields did a great job for the Soviet Union during the war, imagine a war in 43 where the Germans occupy Baku, and don't lose those 600k troops. It would have changed the war a lot.
We were very lucky, and worked our asses off.