I saw this little video on the famed F20 Tigershark that never was. This informal video mentions how Pakistan's Pursuit for F16 (along with other nations) was the first nail for the F20. But the F20 was a fighter ahead of time with features that are reflected in the JF17. (maybe in the griphen too
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F16 has complexities and its a medium size fighter, not a light machine and requires more advanced training time to fly it, then paired with other complexities. Thus the need for a fighter which is low cost, easier to fly and maintain with exceptional technological avionics & sensors features found on say a F16 etc.
Strangely vis a vis Pakistan skipping the F20 and hot pursuit of F16 did finally come full circle with the JF17. As F20 is in essence living in the JF17.
Personally I guess the adoption of F-7PG makes sense now! Pakistan could have done with both F16 and F20 too.