Rear launched missile could change the DOGFIGHT TACTICS???

Could the new missiles research put in the trash the tipical dogfight tactics???, since an misile fired against an incoming target (agressor) should hit it before even the agressor could prepare their missiles?? -little confusing 😀 -, look the grafic, the defender (a),the agressor(b), the defender missile (m), and theire speeds Va,Vb,Vm, the Vm (rear fire missile) relative speed for (b) is Vm+Vb, also the back-rocket can be launched from more distance, after almost an century of aviation the tactic of go for the enemy 6s turn useless???….any idea??????? :confused: