I think you're underestimating the F-5 a bit. I mean Thailand recently upgraded a batch of Vietnam era F-5's with AESA capabilities and new avionics. For the cost of production and maintenance it's really worth it. The US navy still uses them. I mean you can transport 4 of them in a 737. It's not a frontline fighter but as a conventional backup fighter it's great.
As for the SU-57, I mean Russia really needs $$$ to produce these. They're only planning on producing 76 by the end of the 2020's, so they need a few nations to seriously invest. The Indian's are being flaky lately, wanting to invest more in western aircraft, so Iran and a few other nations investing a few hundred billion in the SU-57 is really what Russia needs as a pillar for the program.
So far, Iran hasn't shown any serious interest in major weapons purchases from Russia or China but that could just be a game of chicken. Of course by showing interest that gives away leverage. Iran's leaders and military leadership know better than that. Most likely, once the nuclear deal is re-activated, Russia and China will come to Iran and make offers rather than Iran acting needy now.
As for the SU-57, I mean Russia really needs $$$ to produce these. They're only planning on producing 76 by the end of the 2020's, so they need a few nations to seriously invest. The Indian's are being flaky lately, wanting to invest more in western aircraft, so Iran and a few other nations investing a few hundred billion in the SU-57 is really what Russia needs as a pillar for the program.
So far, Iran hasn't shown any serious interest in major weapons purchases from Russia or China but that could just be a game of chicken. Of course by showing interest that gives away leverage. Iran's leaders and military leadership know better than that. Most likely, once the nuclear deal is re-activated, Russia and China will come to Iran and make offers rather than Iran acting needy now.
No doubt flying in your own Airspace increases you chances of survival that fact remains true for any fighter on the planet.
However, in a proper cost benefit analysis you can't simply close your eyes to Iranian F-5 stats in areal engagements against the Iraqi Air Force.
At Iran's level of technology, fixating on improving and producing the F-5 for use as anything other than a trainer as appose to even the F-4 does not make sense to me even at triple the cost it still makes no sense. With a modified F-4 your at least getting the payload capacity, range and air refueling capability to conduct strikes against various types of targets beyond your boarders.
And it's about time Iran moved away from this fixation with the F-5 and the OWJ engines....