You're overlooking the fact that it works both ways. You may not need to manoeuvre so hard to get a firing solution with HMS and other off-boresight features, but neither does your opponent. And you still need the g/turn rate/energy to defeat the bad guy's solution. Take the argument to its extreme (purely for illustrative purposes), do you think you can fly in straight lines shooting jets way off boresight and survive?
Absolutely not. And exactly why we don't turn the BONE into a missileer. The F-35 is NOT an air superiority fighter. It is a strike fighter. It's primary role is air to ground, yet has a credible self defense capability. It is not designed nor intended to go up against an air superiority fighter.
Are you suggesting that we plan on NOT going against a foe that has any of those qualities?
I don't know who "we" is in your statement, but USAF has a dedicated air superiority fighter to go up against such a foe, and it isn't the F-35. Once again, the F-35 is not an air superiority fighter nor was it ever meant to be.
If other air forces have plans to engage a foe that has 4+ generation air superiority fighters, then they should buy something other than the F-35. Can you name a 4+ generation air superiority fighter that is currently in production that they could purchase instead?
If other air forces only buy F-35s, then yes, I am suggesting they should not plan on going up against a foe that has 4+ generation air superiority fighters and the will and training to use them. How many such foes can you name?
The Royal Navy is getting F-35 as its only fast jet. Are you now saying that it won't do the job for them?
Maybe. Maybe not. Depends on what "the job" is. If the Royal Navy's "job" is to engage a foe that has 4+ generation air superiority fighters, then no, probably not. Just as the Royal Navy should probably not have planned on engaging a foe who had 3rd or 4th generation fighters when all it had was Harriers.