A4 skyhawk and F5 in 80's is more like F16 or Grippen of today,
Not really.
I said the 80’s so lets pick a specific date like the middle year 1985.
The production run for the A-4 was from 1954 to 1979.
Malaysia bought their A-4 second hand in 1982.
It was already obsolescent by the time Malaysia acquired it so much so that Malaysia had to upgrade it to the PTM model.
The F-16 and Gripen are still in production and in services in a significant manner today.
You can make a stronger argument in the case of the F-5E.
It’s production run was from 1972 to 1987.
Malaysia acquired theirs as new builds from 1975.
It was in production and a contemporary fighter at the time.
However, the whole purpose of the F-5E was that it was to be export oriented.
It was never in service with its home air arm (USAF). And only as an aggressor for the USN.
With regards to timing in its life cycle, yea you can make a very vague arguement that it is analogous to an F-16 or Gripen today.
But not really, as its really comparing apples to oranges.
However, Malaysia bought its F-18D in 1997 and SU-30MKM in 2003.
Both those were not only firmly within their production runs but also considered top tier threats at the time of their acquisition.
You can not say that for the F-5E and A-4PTM in 1985.