I would suggest that the inability to recover development costs from sales (historic and future, IMHO) puts the concept of supersonic airliners firmly in this category.
Read the "Sporty Game" by John Newhouse
PD. Even those we might consider successful never recovered development costs. Among others he quotes the DC-9, DC-8 and L-1011 ($2.5 billion in the hole). So the Concorde is no different, except in the former it was shareholders who paid, and taxpayers in the latter.