As much as I love the lines of it, over time it did have other things going against it. In later days it was more of a prestige mark for the airlines it served.
Financially unviable is only the tip of the iceberg for the Concorde. When an aircraft like that of such size goes supersonic often enough, it doesn't matter how well it got engineered, it will start to shake itself to peices just as a matter of course. There is also the issue of changing engine emmission standards in both exhaust content and noise levels, the Concorde is neither quiet nor clean, those Olympus engines just don't cut it in the emmission control department. Then there's the cost, who can afford to ride on one of those? Big execs in suits and rock stars, thats about it.
Concorde is a beauty, no two ways about it, but all good things must come to an and and all things mechanical become obsolete (except maybe the C-130 Hercules, 40 some years going strong in both military and civilian circles and STILL new models of it coming off the assembly line. That is trully an aircraft for the ages!)