An additional issue with supersonic is it doesn't save you time waiting in line at the airport or driving to and from. So the net comparison isn't 3.5 hours vs

An additional issue with supersonic is it doesn't save you time waiting in line at the airport or driving to and from. So the net comparison isn't 3.5 hours vs 7 hours of flight time (Concorde vs 747, New York to London); it's more like 6.5 hours vs 10 hours of total cab + airport + flight time. Either way, you're probably tired from the trip and won't be particularly productive, so why not pay less money for a more comfortable seat in a bigger, slower jet? (While I never flew Concorde, I did babysit one in a museum. There isn't a single seat that isn't cramped -- even in the cockpit.)