In the 1950s and 1960s, when the F-4 Phantom came out with its ability to use Beyond Visual Range (BVR) missiles like the AIM-7 Sparrow, the United States Air Force (USAF) and United States Navy (USN) declared that dogfighting was obsolete, that from thereon, air-to-air combat was going to be limited to whichever side had the better system. That was why both branches stopped training Air Combat Maneuver (ACM) training to their pilots then.
Then the Vietnam War came along and problems with the use of BVR missiles started coming out. First, there was the engagement problem wherein you need to be able to identify your opponent before shooting it down. If you can’t ID it, then you can’t shoot it down, so the F-4s had to fly in close to ID the aircraft. Second came the reliability issues wherein the Sparrows weren’t being maintained very well, and it also turned out that their electronics were a bit too sensitive for field use so they ended up having high failure rates after launch.
Then came issues like maneuverability (i.e., the early Sparrows couldn’t maneuver to follow the evading fighters), ground effect (i.e. low flying aircraft were harder to track), etc. which made the Sparrows even more unreliable in combat.
This resulted in a low kill ratio for USAF/USN fighters as opposed to Vietnamese fighter aircrafts, and the while the USAF attributed this to the lack of guns on their F-4s, the USN simply started training their pilots in ACM again (hence the birth of “Top Gun” school). The result was that the USAF, even when the Gatling gun armed F-4E came along, continued to have mediocre kill rates in Vietnam, while the gunless Phantoms of the USN ruled the skies over Vietnam with a 14:1 kill ratio.
Much of those problems with BVR missiles have been addressed, but you never know, since you can’t underestimate human ingenuity. If there’s a will, sometimes there’s a way.
That’s why the Americans, even with all that BVR technology improvement, still chose Lockheed’s F-22 Raptor as their next generation fighter, which was more maneuverable than F-23 since they were determined not to make the same mistakes of the past wherein they thought maneuverability was passe.
What’s next in aircraft technology? Take a long, hard look at those “Active” Defense Systems being used on the latest tanks, wherein projectiles are used to shoot down incoming anti-armor missiles. If successfully adopted on aircrafts, they could negate the effectiveness of most air-to-air missiles, which means ACM could again become an important factor in air to air combat.