I'd like to add a few words to the discussion a few posts earlier about the reasons of the commercial failure of Concorde.
Concorde killed by Americans.
This is an article published in a very famous french magazine in 1972. This article describes the various measures taken by the american to stamp down the european aeronautic industry and more particularly the Concorde.
According to this article, it started with a campaign to warn the US Congress about the supposed stratospheric pollution that SST would create. The danger was off course exaggerated but nevertheless the congress refused to vote credits for the american SST. That is the main reason why Boeing stopped the development of their own SST. Harold Johnson, from the university of Iowa, even affirmed that the SST would destroy the ozone in the stratosphere and, as a result, decimate the humanity with uncurable skin cancers and retina burnt.
Also, US firms proposed to South American companies to buy back all their Caravelles at catalog price if they promise to buy only boeing aircrafts for the next 10 years with credit over 8 years and only 2% interest.
And, finally, the Export Import Bank (Eximbank) whose many arilines's cash depends on, announces that they will not give any loans to buy european aircrafts. On top of that, some political pressure were also used to discourage some countries that could be interested in buying european aircrafts.
Under those circumstances, Concorde, despite its incredible technological advance, had almost no chance to become a commercial succes.
It is intersting to note that Concorde came to life thanks to political decisions but also never really took off partly because of political reasons.