For the off bore sight targeting with missiles, particularly the IR missiles, this is true.
But there is no off bore sight targeting for guns. If you have to really get down in the weeds and go mano er mano with guns, you better keep that manueverability.
You can expend all of your missiles, you can have more adversaries than you have missiles...and may need to get down to 20 mike mike (or whatever mike mike you carry), so I'd keep that super manueverability for that for sure...and for evading some of those missile critters too while using all the counter measures in your bag of tricks.
Of course I agree with you completely, but the current fighter philosophy seems to have returned to a multirole fighter, with more emphasis on G2A than A2A, I note with some consternation that the Navy C doesn't have an internal gun??? brat