The range on the AIM-120 isn't particularly good, I don't know if the current AIM-54 in game is modelled accurately but it seems to perform a lot better, assuming you (F-15) are the only target, I can fire off missiles every few seconds and you'll have to dodge 6 AIM-54's before you'll even get in range and then you have the AIM-7 to deal with, or I can turn back to base and let you play with uncle SAM.
I think people have also overlooked that players can simple take off, fire off at 6 targets, wait, then land, rearm and do it again, without even getting in an enemies range.