1) I am repeating myself but it is to do with immature BVR technology in past wars. In the Bekaa valley, BVR was mature but was not used as the fighters were so close to each other anyway in the crowded Lebanese skies.
2) One BVR missile may have 50% chance of destroying the opposing plane while with 2 the success rate goes up to 80%. You need to make sure that you definitely shoot-down the other plane so no harm in using 2 out of your 6-8 BVR missiles that your plane carries.
3) BVR planes are still fitted with WVR missiles and guns as you need weapons when you are up close to dog-fight. BVR will not always win the fight for you 100% of the time but that does not mean it won't take out 80% of the enemy planes before you even see them.
4) Chances are most of the 12 planes would be shot down by BVR missiles before any of the survivors can get within WVR range.
1) The average BVR killing record so far is only 2.8% of the total firings. Who told you there was no BVR firings in the 1982 Bekaa valley air war? There were a total of 23 BVR missile fires that killed only one plane. The BVR killing is only 4.3% or one killing. Please read that war history before you come with denials.
2) So, one BVR missile may not have more than 2.8% or less chance of killing an enemy plane.
3) There are radar missiles, when fired at about 37 km distance or beyond are called BVR missiles. When fired and killed from within visual distance even by radar missiles it is no more called a BVR killing. It is called Within Visual Range (WVR) killing even if radar missiles were used.
4) No, not all the planes will be killed at BVR distance. The past war records show not even one plane will be killed by one BVR missile depending upon the situation. This is why the BVR killing rate is so low. The warring planes are not static bodies. They move at near Mach-1 speeds.
The radar of the enemy plane immediately gives warning signals to the pilot and he takes the plane away from the path of incoming BVR or WVR missiles. When the enemy plane is far off, say, at 40 km distance, the enemy pilot may even neglect the incoming BVR missile, because it will miss and only by luck it will hit. This is why the rate of killing is 2.8% or less.