This is all very interesting.
I remember trying to define the curse as being an abstract curse against technology newer than whatever was current. And if one Kingdom was more advanced than the others, the limit was put at the most advanced kingdom, so the others were allowed to catch up. Anyone can built up to that point, but then things start to fail.
Like even though Wormholers generally work, there are times where guns randomly stopped working, like when Vladek tried to shoot Thingguy in Perpetual Doom, or when IntreFusEclps's unverse manipulator didn't work in the dungeons.
Well the sorceror is dead so at this point perhaps the curse is just an annoyance that doesn't always inhibit advanced tech from working, but it does enough to be annoying, and make things unreliable. However its influence wanes the farther away from Dewin is, so the airship from F&H works because it's far away from Ankoria.