The thing that hurt the Concorde most was that it created a sonic boom, thus precluding it from flying supersonically over land. Because the 20XX is subsonic, it won't suffer that problem. And because it will be flying the same distance in less time, presumably it will use less fuel. Of course, that assumes that it is as fuel efficient on a per/mile basis as a 767/777/A340/A380. The direction of the airline industry seems to be going more toward point-to-point long distance service. See, for example, BA's new nonstop from San Diego to London. You couldn't support an A380 or a 747 on that flight. But because you can support the seats on a 777/767 on that flight, you could use the 20XX for that route too.