Maybe part of the problem was that the Allies were, bluntly, more pragmatic.
Part of the misleading hagiography of German technology is to realise a lot of their inventions were... kind of shit. The Tiger, for instance, was in ways a great tank: great gun, great armour, decent manoeuverablity. However, it was ultimately a failure: catastrophically expensive to make, difficult and expensive to maintain, and highly unreliable. Given industrial warfare is actually about pumping out huge quantities of robust, adequate equipment, you'd be considerably better off with three times as many Panzer IVs. By the time you get to the Maus, it's 200 tons of sheerest stupidity that the morons in at the top couldn't even understand would be useless.
But that's part of the appeal, really: the fantastical overambition and obsession with size and grandiosity. By and large, the allies also thought about some creatively stupid stuff, but it was usually a lot more "niche" or buried much earlier.