Even if the Germans were willing to pursue a Manhattan Project of their own, they didn't have the industrial capacity to divert to build up the infrastructure f

Even if the Germans were willing to pursue a Manhattan Project of their own, they didn't have the industrial capacity to divert to build up the infrastructure for it (let alone support the ongoing resource commitment it'd require). Hell, they didn't have enough to adequately support their war effort even considering Speer's efforts after he was appointed Minister of Armaments. The political games between top Nazi officials, the refusal to mobilize women as factory workers due to ideology (good German women stayed at home and plopped out babies, basically), and the reliance on slave labor all helped the Germans thoroughly screw themselves. I like this quote from William Knudsen, which really sums things up: "We won because we smothered the enemy in an avalanche of production, the like of which he had never seen, nor dreamed possible."