But what if IAF goes for 5th gen procurement in coming years
Unless the IAF gets the F-35, the IAF's FGFA is about as far-out as the PAF's plans (but the PAF can obviously track sooner by slotting in the FC-31).
However, a FGFA isn't a counter to a FGFA. Rather, a counter to the FGFA is having the right sensor deployment and advanced enough air-to-air missiles (AAM). You could get both with a 4.5+ gen fighter, like the J-10CE, provided you have the subsystems.
If Bilal is right and a true 5th gen Pak project is pushed to 2040-50, then something else will need to be built after the JF-17 run ends. I think here a larger, stealthy single seat and low cost design fits in. Something like a big brother to the JF-17 like the Hornet - Superhornet.
Unless Pakistan plans to import planes only between the last JF-17 and the first 2040-50 true stealth, that seems the logical conclusion.
Sure, Pak can have a few squadrons of J-35s as a tip of the sphere, but this iteration will give the PAF numbers, just as the JF-17 does today.
Based on the CAS' statements, the general idea I get is that an FGFA is supposed to be in the fleet by 2047. So, that could mean an induction period as early as the late 2020s, or as late as the late 2030s.
Basically...
If the PAF selects the FC-31 or J-35 route, then we're looking at the late 2020s, so the switch will happen after the Block-III. But the first operational unit of the FGFA is likely a 2035+ thing, though production can be in full-swing sooner.
If the PAF selects the CAC or TF-X route, then we're looking at the late 2030s. To be honest, if this is the route, then I think the PAF will actually just buy lots of J-10CEs off-the-shelf. It doesn't help industrialization, but the decision-makers at AHQ et. al aren't industry experts, they're combat operators.
So, from their standpoint, what is there to lose with the J-10CE? The JF-17 Block-III is literally going to use the same weapon systems and many subsystems. I think the only point of interest will be adding Ra'ad/Ra'ad II integration. Otherwise, it's a net-benefit over the JF-17 program as-is to-date.
What will PAC do in the mean time? Well, I think it'll try building an actual prototype of the FGFA in that time. It'll, ideally, become very engineering/R&D heavy while the mass production element goes off to the private sector. That labor/resource can take up the mandatory offsets (via civil airliners, helicopters, drones, etc) the PAF links to its FGFA selection (supporting Aviation City is a must).
I'll put it this way as well. If you commit to 180 J-10CEs by 2040, you can confidently ask for deep ToT for the FGFA, and a serious (100%+) offset on the FGFA (sharing the production of the FGFA and/or have China buy from other related industries, like airliners).
@JamD @kursed
Overall, there are ways to get creative with all of these issues, we don't need to become dogmatic to one extreme or another.