That proven khatara is technically better than non upgraded f16 block 15/20 of mid 80s.....mig 21 bisons can carry r77BVR and has a decent radar of 1990s-2000s standards...
It is also set up for VR combat : Mig-21 is an interceptor not air superiority.
An interceptor's job is to intercept. Which means, fly faster than the enemy fighter jet and catch up to it.
As a result, Mig-21 is a shit dogfighter : its built for straight line speed, it turns like a freaking elephant in a clogged road in kolkata.
Its mission profile isnt that of a BVR fighter like Su-30 or its 5th gen fighter developments like F-22.
These planes main mission is to detect enemy at radar, achieve radar lock, fire missile and immediately take a U-turn and bug out.
Its mission profile isnt that of a Su-30 or a MiG-29 or a F-16 or a FA-19. Those are dogfighters - they are meant to dance close range like boxers trying to box each other.
Its mission profile is that of an interceptor. Which is run very very fast up to the enemy in a straight line, catch up to him, hit him over the head and make a really YUUUUGE sweeping turn (coz u turn like a bathtub) and then run the hell back.
Interceptor.
Abhinandan's mission profile seems to suggest he intercepted the F16. Not dog-fought it to death.
A MiG-21 cannot dogfight a F16. Impossible.
But an F16 cannot outrun a MiG-21. Also impossible.
In fact i am fairly confident that Abhinandan was in an intercept mission because interceptors fell outta fashion in the early 90s and no one practices against intercept missions anymore -we all practice BVR and dogfighting. Thats all that is done in Red Flag or any air exercise.
So i think this is why PAF didnt suffer loss to Su-30 or Mirage-2000 or others : it is trained in BVR and dogfighting and can recognize enemy aircraft patterns for it - its not practiced in intercept missions (no one is, except for us, chinese and russians) and therefore did not know what the heck to do when a straight up interceptor came and intercepted it.