The fact remains taht there is not the demand for a large fleet of supersonic a/c. Although everybody wants to get to the destination more quickly, most people are not willing to pay. Although some Concorde pax will claim that it makes them more effective, Concorde is basically marketed for its unique capabilities, being the only a/c in which ordinary pax can go supersonic. There has never been enough demand to utilise all Concordes on the trans-atlantic route (trans-pacific not possible and no other route found to be profitable), many were used for charter services. There were reports several years ago of a US business jet manufacturer (Gulfsteam??) teaming up with a Russian design bureau (Tupolev??) to produce a supersonic BJ, but nothing appears to have happened with this project