>flares pointed backwards

Why would an onboard missile logic system in year 2025 ever change target to a new vector suddenly directly opposite of the original target path?

Is it just a sad hope that the hostile missile system is that archaic + the defending aircraft will be far enough away from the rear pointed flares that it'll -usually- increase survivability, or is there something else I am missing?

There is no way missiles are still being produced in 2025 with such shitty path prediction, right?