The V1 was more cost effective - not because the V1 did much damage, but because it diverted a great deal of British effort at trying to shoot them down and blow up their launch sites. The Germans eventually figured the latter out, and built lots of fake launch sites for the RAF to uselessly destroy.
Missiles only became effective due to better targeting or nuclear warheads.
Von Braun was not because Russia had also captured a number of rocket scientists, the US rocket technology was way behind, and von Braun was needed to get the US rocket program going.
Modern liquid fuel rocket engines can directly trace their evolution back to the V2.
However, if you combine it with modern image recognition and you know your target it will be probably enough