There are a lot of reasons we haven't gone supersonic with air travel. Sonic booms do things like shatter windows, set off car alarms, drive animals nuts, etc. The concord flights had to wait until they were 100 miles off shore before they would go supersonic, and they were also extremely inefficient, which means extremely expensive. It really is not cost effective for any airline to do supersonic flights right now, although Virgin has designs on a sub-orbital plane that will fly from New York to Paris in something like 2 hours.
There are also new airframe bodies that do not produce a sonic boom when they break the speed of sound, but I'm not sure how efficient those are for air travel.