Not suggesting a blank cheque in any way shape or form, merely pointing out that this particular stage where real fixes can be made to real aircraft to correct real problems ought to be treated as such, rather than as the end of the world. You don't can a programme if it hits a problem. You find out whether it can be fixed, for how much and then make a value judgement.
LO - I agree, whether it all had to be LO or nothing is debatable, particularly if treating A or B as Hog or Harrier "replacements". However, we are where we are and as far as the US goes, there ain't a plan B. If you look whta is happening with US Naval shipbuilding, the F35 / FA18 analogy is right there with DDG1000 and the DDG51 Flights III & IV. Funny old thing, the "cheap" 51 restart ain't actually all that cheap anymore.
Moral of the story is probably to buy fewer numbers of new designs more frequently. That way people haven't forgotten how things are done. Economies of scale are not absolute......