If they didn’t they do now. When the US hears one of their rivals (everyone) has some military tech they don’t, they will immediately create their own version of it but better if possible. Even if the military tech doesn’t actually exist, they will create it.
That happened with one of their fighter jets though I can’t remember which. The soviets said they had a hypermanuverable jet with crazy specs and the US created one to match it. The Soviets had embellished the capabilities of their jet. No such jet actually existed… until the US built one… with even better capabilities because they fell for the ruse.
Anyway, moral of the story is that if there’s military tech the US doesn’t currently have and it becomes known, the US will immediately make their own
Edit: Found the planes! The American fighter I mentioned is the F-15 Eagle. The Soviet one was the MiG-25.
The F-15 was built because the Americans felt they needed “a pure air-superiority design that would be able to meet the expected performance of the MiG-25.” It exceeded them, by quite a lot, becoming one of if not the best fighter jet. No F-15 has lost in aerial combat, ever.
Also fun fact: it is the only fighter jet in history that has ever made a successful landing after losing a wing.