Also, the US funded and sponsored WWII - or elements on Wall St did.

It's tempting to wonder if there was a genius-level Machiavellian plan to destabilise Germany and neuter the UK by sponsoring a self-destructive psychotic lunatic, leaving a hegemonic gap to be filled.

I suppose it's possible, but there's little evidence that US diplomacy is that sophisticated.

And had the UK lost the Battle of Britain and been invaded, the US would almost certainly had sued for peace with Hitler.

As it was, the most valuable payload left over from the Nazis was a bus full of rocket scientists and the odd psychotic quack, all of whom were collected during Operation Paperclip.  

That might be misleading. The USA was important for supplying war material via Lend-Lease, which began in March 1941 and benefited China, Russia and the UK. From 1942 forward the US growing presence in the UK and their activities in North Africa and Italy complicated things for the Axis Powers. Germany was unable to totally concentrate on Russia. While it is true that Hitler had badly bungled Barbarossa, had he not had to be concerned with Africa, Italy and a possible invasion from the UK and had the UK not had the support of the USA things might have turned out more favorable to Nazi Germany. A negotiated peace might have been the result, with Germany being the hegemon in Western Europe. Certainly Germany would have had better access to the Ploieşt oil facilities, which had been important for Barbarossa, than it had after US bombing efforts out of N. Africa in 1943.

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."