PAF was denied spares in 1990s as was india but times have changed, i dont expect this happening again
f-16 are still available but not subsidized but since when were they ever subsided before? answer is never
USA offered subsidized as they knew PAF is not going to pay full price for fighter for which it can get 3x jf-17s, yes if they are priced at thunder price than ok. and that was the deal
f-16 also has an AESA, a better engine and better avionics
airframe of C/D is 80s design vs 90s design of gripen/ rafale but u have to admit that f-16 was years ahead of its time, so was the f-22 and the f-35, would you call f-35 obsolete in 10 years when europe finally catch up or will you call f-22 obsolete even though it was inducted before rafale?
as for end of its time, no sir, even the USAF is going to operate it till 2040 per its new planes, other countries might operate it beyond this
as for gripen, not even a single C/D model has been inducted which is a radical upgrade of earlier model(as was C/D F16)