I'm not sure. By the time the Reich's economy really starts to collapse he may be dead or overthrown. If not we are looking at a 1970s era USSR. The Soviets were able to keep kicking the can down the road for almost 20 years as things got progressively worse for the WP countries and then the non-Great Russian parts of the USSR, and finally even into Moscow (toward the end in the USSR women, who were the primary shoppers, and some men, never left the house without a couple folded up string bags. If they saw a queue forming near a shop they would automatically join it, not because they necessarily needed what the shop sold, but because they might be able to by something, anything, to barter with later.). IOTL the Soviets always kept the specter of War on the table whenever they needed something (U.S. grain was a regular item of interest, U.S. would sell it at massive discounts, partly to prop up U.S. farmers, but also to keep the wolf from Moscow's door lest the Kremlin decide to go and get what they needed behind a wave of T-62 and T-72s.) The Reich could do the same thing, at least for a while.
Speer would be interesting. For one thing he was anything but an inspiring or dominating leader. Technocrat to the core, very practical, as one would expect given his professional training. I rather dount he would last long atop the viper's nest that was National Socialism. Himmler would likely have him "die in his sleep" inside a month, might take Gobbles two months. Heydrich would probably just shoot him between the eyes over a beer. Charlie the Tuna in a tank with a Great White.