Ken I'm sure you are right - that it is designed to work in groups - however history tells us that you can't guarantee how you will have to fight in reality. “No Battle Plan Survives Contact With the Enemy”
No one is making any "guarantees", and may I suggest that any demands for such are absurd. Look at the data: in a 4 v 8 scenario the exchange rate is 1 to 6, and NOT 0 to 8. So no, 5th Gen does not make you an invulnerable Superman, and yes, 5th Gen operators will lose some airplanes. The idea is to make the enemy lose far more than you, it is NOT to make sure you lose none.
Further, one can design and build for the 3rd percentile worst case air-to-air scenario. F-22 did that. F-22 is even more expensive than F-35 AND it has a
lousy air-to-ground capability. Once again, F-22 is optimized for air-to-air and has traded a
LOT of air-to-ground capability for that stellar air-to-air performance. F-35 is optimized for air-to-ground and has traded
some air-to-air performance to get it, with the idea being the F-35 pilots will avoid the low probability close-in dogfight for which they are not optimized. Industry was able (
eventually) to figure out how to build a 4th Gen aircraft very good in both air-to-air and air-to-ground performance (F-15E and later, F/A-18E and later, Typhoon Block 15/FGR4 and later, Gripen NG and later, etc). But we are not yet able to build a 5th Gen aircraft stellar in both air-to-air and air-to-ground performance. May I politely state that demands for such at this time are absurd.
the other point is that I doubt many (?any?) of the non -US buyers will have the IT, networking and other sensor capability to actually form a "group" - they're planning to use the F-35 as a straight replacement for 3rd & 4th Gen aircraft
Well, if you think that every nation other than the USA is hopelessly stuck in 4th Gen thinking and 4th Gen operations, and incapable of 5th Gen operations, then I would politely suggest you think again. My opinion is that the nations that bought into the F-35 program understand the value of the 5th Gen fight and are buying into it so they can fight a 5th Gen fight, not a 4th Gen fight. Those nations that are incapable of moving into the 5th Gen world can buy (and indeed many are buying) Rafale, Typhoon, Gripen, F-15, Super Hornet, Sukhoi, etc.