Wonder weapons, in general, aren’t. Rather, they’re old weapon designs finally catching up to the original hype:
Take smart bombs. They were invented, and used quite successfully, during World War II. But these were radio controlled, and required skilled operators to succeed. Expensive as well, and no one wanted to spend the money to train effective operators in peacetime. In wartime, price was no object, and experience was easy to get.
Thus the U.S. dropped smart bombs from their arsenal after World War II, and didn’t revive them until the 1960s, when lasers (developed a decade earlier) were used to bounce their light off a target. A bomb was equipped with a seeker that could home on the reflected laser light, and a guidance kit (battery and motors to operate small wings) to hit the target without an operator. This was cheaper and more effective than the earlier smart bombs. The next big jump, in the 1990s, was the GPS guided bomb, which finally perfected the smart bomb. Thus this wonder weapon took four decades to become an overnight sensation.
Then there are helicopters, guided missiles, air-burst grenades, electronic warfare, body armor, and combat robots.