I think Russia would have continued on long after Moscow, they already had a contingency plan. That was Stalin’s nature, he would have fought on till the last 10 year old Russian girl was killed. Slaughter of his own people was acceptable to him.
France and Italy, well we know what happened with them. I would like to see Vichy recognized even if its as simple as certain French colonies became pro axis neutrals with a set # of inf to def, where others stay blue (Free French).
With UK consider maybe Germany didn’t blunder and was able to capture/kill the majority of the English at Dunkirk. England was pretty vulnerable (US still not in the war). Hitler didn’t play by the same rule book, and could have threatened to execute all prisoners if a deal wasn’t worked out (maybe he did idk). That would have been many more lives, and of course a huge chunk of the English fighting force that allowed them to continue the war. I still think that the UK would have moved its base of operations to Canada even if it signed an armistice, or there was a successful sea lion. Canada was separate nation and could have continued the good fight. The Brit’s were much more under handed then the French, so I don’t see a conflict or confusion of British commanders like there was with the French. The British ships and over seas units would have just flown under the Canadian/Anzac flags I would think (which would have really pissed on Hitlers parade).
The USA defiantly had the resources and will to continue, if by some miracle the E or W coast fell into enemy hands. Its not like the axis could mount that kind of invasion anyway, but say they where able to take token victories, its a much longer line of supply then say from Berlin to Moscow. I guess the axis could have maybe sued for peace w/US if all of Europe and Asia was in axis hands (all other allies signed an armistice), and the US was totally isolated. I don’t see that deal including occupation though, it would have been more along the lines of you stay on your side of the oceans and we’ll stay on ours. The only other way they could have put the US out of the war is if they got an atomic bomb and used it, and the US didn’t. Even if the axis would have got all the allies to sign deals, at some point war would have continued because the axis wouldn’t have had the policing force to patrol all its enemies IMO.
Anyway after all the babbling I also think there should be a mechanism to continue on in certain circumstances. I wonder however if it will just turn out to be an ally advantage. If the allies take Tokyo/Rome/Berlin then (unless there’s a terrible blunder on the axis part) those powers are normally beat back with nothing else left just by the nature of there locations. Japan doesn’t have a commonwealth (safe place) China hates them. I guess Jap could continue in Asia or India if it had IC. Italy would just be done as it was. Germany could have some options, but a smart ally player would take those away before they dropped the hammer. Same could be said for Russia unless your using some type of mobile industry.