Well, the missiles in Vietnam weren't all that great. Besides, the MiGs back then tried to sneak up on the pilots by going low. However, with the modern AWACS they can't do this. Back then they could since the radar on the ground had a blind spot for planes flying very low. Now, AWACS prevents this since it is airborne. Therefore, its blindspot is above it. This means ground based radar can cover for it.
And I don't think Kyle's being rude. He's just pointing out a well known fact. However, this topic is indirectly related to engine limitations. If I'm correct, everyone else is talking about how to get realistic air combat into ofp. Engine limitations are a side effect of this subject.