I think we have reach the point of splitting hairs on the general question. I said "unless stopped, he was going to get it", which is rather obvious naturally. An alliance to check Hitler would count as such, no?
That' absurd logic. That could be argued but how you just phrased it would be like saying anyone will have anything they want "unless stopped", with society being the factor stopping them.
It would be like saying "unless stopped" some random spree shooter is going to "kill everyone in the world". And then if someone pointed out how absurd that is because the police will overwhelm them relativity quickly and they couldn't travel that far and wide and you turn around and say "well that would count as something stopping them now wouldn't it"?
I guess it would depend on the demands of such a peace with Britain would be and if it included demilitarization, he could always turn his attention back to it after the USSR and overrun it.
Britain will never
accept demilitarization, for reasons you just stated. Nor will she cede any colonies. A white peace is all the Germans can get.
As for 1940 a combination of an effective sea strangulation (assuming the absence of Lend-Lease and such), there is a scenario where Britain can be isolated enough to be defeated. Planes don't fly without oil and once the supplies were depleted they could be bombed into subsmission and then invaded.
A.) I would assume that even in a timeline where Germany wins WWII there would still be lend-lease, at least to the UK.
B.) The Kriegsmarine isn't as capable as you seem to be giving it credit for. The Royal Navy was much more powerful and had plenty of destroyers. Don't get me wrong the Germans can devastate British shipping but I don't think they can fully cut it off.
C.) Even if Germany gains air superiority over England how will the Germans launch and sustain this ground invasion? All they really had for transport were Rhine river barges and you better bet the entire British navy will steam into the channel if that's what it takes. Then the British will deploy mustard gas on the invading Germans when they hit the beaches.
D.) Even if Germany somehow successfully invades and occupies the UK I would say it could ultimately be a net-negative. We would have a situation where Germany needs to deploy even more
troops in the West (France & UK) to occupy the UK and finish off resistance after a bloody battle. Ironically this would make Germany weaker
relative to the USSR in 1941. Not to mention that Stalin will be expecting the invasion this time, as the UK is gone and he is clearly next on the hit list.
If Hitler has to delay Barbarossa until 1942 it's over for Germany. The Soviets will have completed their military reforms and will be ready & waiting for the German invasion.
Also, Hitler's insanity drove him to to many stupid decisions I would point out.
While this is true we must remember that he more or less did everything right up until about the Fall of 1941 after the Battle of Smolensk. If anything even bothering with the Battle of Britain was his biggest mistake up to that point. The UK could have been left alone as they had been neutralized. Absent bringing America into the war the British can't summon the raw manpower required to launch a serious landing in the West.
The biggest mistake ultimately was declaring war on the United States.