The Russian had so much of everything and it wasn't just from what the American and British gave them. Their war factories was like American war factories. They never stopped and maybe made more tanks and guns and vehicles and airplanes than the American war factories did.
You may want to revise your opinion on this.
Soviet factories did indeed stop for some time (not competely but still), quality did drop too, and if not for US/GB assistance, 1942 could have ended in an even less favourable position for them.
A full defeat is maybe a stretch, but who knows ?
On Britain defeat: once the airfields destroyed, and provided no war in the East nor against US, with german air superiority Royal Navy may not have tried its luck into the channel with battleships, so again, who knows ? Not in 1940, but 41, 42 ?