US relates every weapons need of Pakistan with COIN/CT ops. It ignores Pakistan's need to maintain military strength against a bullying neighbour. US refused to sell AIM-120D & AIM-9X to Pakistan. In future if PAF wants to upgrade to F-16V standard, there are high chances they will refuse AGAIN.
Dear sir, try to look at US perspective in this case, US did refuse to sell Aim 120D because it was barely developed till 2014, but they did sell you the Aim 120C5. Also Pakistan has actively engaged US forces through it's proxies in Afghanistan. if you keep antagonizing them, they will push back on strategic sales.
Recently, PAF wanted to buy 8 F-16 Block 50/52+ aircraft (which was to be followed by 10 more). US approved the sale but refused to release 430 million USD as military aid. It was easy for Pak to pay the remaining 270 million USD. PAF wants to replace old 3rd gen aircraft with 4 - 4.5 gen jets & F-16s are ideal as they are already in service.
US government had approved the sale, White house even lobbied for the sale, it was the US's elected representatives that declined for subsidizing Pakistani military purchases. If you want to buy F16's pay the entire sum for it.
Why will PAF pay more than US$ 1.5 billion for 18 F-16s when the better Su-35 costs the same or even slightly less (Kommersant reported PAF has requested an initial batch of 6 Su-35's for US$ 500 million).
With highest regards, it would be foolish to get Platform any less than two squadrons to arm any airforce around the world. Even if Russia decides to give you 6 SU35's for free it would end up costing more than the 18 F16's within a decade to operate a new platform, support infrastructure, consumables, service, training and tactics.
If PAF fails to get Su-35, it will look at Chinese options like J-11D (which will be ready for production in a year or two).
There was a statement by an official which clearly said Pakistan will look at Chinese & Russian options for fighter jets and purchase of new F-16s from US is not possible (even in the future).
As far as European options like Typhoon are concerned, Pakistan doesn't have those "billions" required to purchase these aircraft.
How about this, do some simple arithmetic. Calculate the defence buget for Pakistan, then calculate the Air force budget, substract the Operations Budget (salaries, consumables, service) you will be left with capital. Once you have the capital budget subtract the allocations for Jf17 new airframes, helicoptors, UAV's and other aquisitions. With the left over money tell me how many Chinese or Russian platforms can be bought yearly....
-cheers