Let me explain that this is exactly what you said.
it is a quite capable PESA and perfectly fine for its time and still capable now
It is up to you think upgrades may or may not be done, but the bottom line is that this radar is not perfectly fine.
It's perfectly fine for the role in which it is intended.
I've already explained that, and if you feel like it has a different role to what I described, then make your case in that vein instead.
Otherwise, I have nothing else to add to what I've already made very clear.