At todays Jet 1 A US fuel price of $3.07 per gallon it would cost $108k to fill the Concord. Which holds 120 passengers. That comes out to a cost of $900 per person passenger on a full fight.
If the cost of fuel were double like a few months ago then that cost would be $1,800 per flight.
Compared to a Boeing 737 which has a fuel cost of ~24k at max capacity of 7,878 gallons at todays prices. A passenger limit of 177 and a fuel cost as low as $136.64 per passenger on a full fight.
Thus fuel while expensive wasn’t a deal killer over most of it’s history as long as they could keep most seats filled.
There was enough demand for one return flight a day carrying a small proportion of the overall passengers on the immensely-popular with wealthy people JFK-LHR and JFK-CDG routes. That wasn't enough to utilise the 14 production aircraft properly, never mind enough demand for it to have been viable as an airframe programme ...
That said, boom is building a significantly smaller aircraft which should again open up more possible routes.
Yes, and this was mostly necessary because of the small unit counts and small number of routes, not because of fuel costs (though the latter certainly did not help.
Both could be significantly better with Boom: more routes, and lower fuel costs.
