The US lost in Vietnam it is as simple as that. A war is conducted with objectives to bend the enemy's will to your own.
The US went into Vietnam with the objective of keeping the Communist Party out from Southern Vietnam. They failed, so they lost the war.
You could argue it wasn't a fatal loss for the US but it was still a total failure.
Ynetnews says 20 heavy fuel mixers @ $2Mn each and resuming operations in 2 years seems rather long. Source below
Even if the mixers cost 2 million each (doubtful) and they hit 20 of them (doubtful) that is 40 million. A single F-35 costs over double that.
You believe that news story littered with obviously wrong and bogus statements like this?
Solid-fuel missiles, produced using these mixers, allow greater precision and defense advantages by avoiding the need for visible refueling seen with liquid-fuel systems. The solid-fuel propulsion improves both strike accuracy and durability, offering precision within a meter and increasing resilience against interception.
Total bullshit written by someone who does not understand anything about missile technology.
The Falcon 9 rocket from SpaceX manages to land on target and it is powered by a liquid rocket. The Soviets developed liquid-fueled missiles stored inside of capsules which do not need to be fueled before launch.
In fact the opposite of what they say is true, because it is much harder to throttle a solid rocket, it is much harder to control its trajectory to make it go exactly where you want to. Which is why the Iranian Fatah missile for example uses a liquid upper stage.
Accuracy is about navigation, guidance, and the missile's own maneuvering capabilities (or lack of them).