Sure. I went so far as to argue everything was still on the line at Kursk. But Hitler did not invade on the sort of calculations appropriate to a Stalingrad 42 or a Kursk 43. The odds were with him in a blitzkrieg, and only in a blitzkrieg. And after the winter of '41-2, it wasn't going to be that. Had the Luftwaffe had the sorta long range strike power in '42 that the western allies had in 43 (high-capacity four-engine jobs like Lancasters and B17s, and a few hundred spare long range escorts - like the P51 Mustang would become), they might have been able to put a stop to all that T34 and plane production going on behind the Urals. They didn't, and the German advantage began drastically to diminish, to the point where all that stuff the Soviets were making behind the Urals bit them on the arse at Kursk. And then, bar a few more million dead, it was all over.
A woefully simplistic paragraph, but I'm just trying to establish that the 'eastern front' was wholly decisive, and that Kursk was probably the last moment at which German victory was conceivable. I reckon that, given the effects on the advance of the '41-2 winter, the only way left to beat as big and resourceful a foe as the Soviet Union, was to have the capacity to strike over very long range. Germany never had that, so they couldn't stop the Soviets gradually adding a hardware superiority to their numerical superiority. Hence Kursk.
So I still reckon D-Day was all about the look of a post-bellum Europe, and the relevance of Churchill and Roosevelt (had he lived) to that disposition. It was about the Soviets, in other words, rather more than it was about the Germans.
Too big a call?
Cheers, Rob.