I didn't overlook development costs, I SPECIFICALLY excluded them, and SAID that I was doing so.

But you can't just exclude them. They are part of the cost.

Of course you can exclude them, to determine whether the aircraft themselves are a viable commercial proposition for the people who bought them (the airlines) -- which they were, just as other aircraft such as the A380 today are. The people who bought A380s are happy, and will be using them for decades. Emirates would still like to buy more (and may end up buying used ones from less successful airlines)

The fact that the aircraft manufacturer spent far too much on development relative to the sales they made is of course important to the manufacturer -- or at least to whoever is financing the manufacturer, but that is a DIFFERENT question. In fact more than one question.

There is the question of whether the price they were sold to airlines for was greater or less than the incremental cost to build one aircraft. If the price was greater than the cost then there was some hope for a successful program, and they simply overspent on development and/or didn't sell enough copies.

If they were sold to airlines for less than the marginal cost then it's just an all-around manufacturing screwup that could never be solved by any amount of sales.

£16 billion in inflation-adjusted development costs is peanuts.

You should look at the costs of the F-35 :)

But of the F-35 there are >1000 planes to amortise the costs over. Which is two orders of magnitude larger than the concorde

F35s are now selling for $81m on average per plane - https://www.airandspaceforces.com/f-35-program-office-lockhe...

And yes, the program is expensive but there will be thousands of F35s by the end of it all (1000+ already)