Concorde had a range of 3900nmi (7200km/4500mi), a 777-200LR has a range of 8500nmi, an A340-500 HGW has a range of 9000nmi
In theory Concorde could perform a one-stop Sydney to LA service (stopping at Cassidy International, Kiribati), supersonic the whole way.
If say the US had come up with something else than just a wooden supersonic airliner (Boeing 2707), I guess swallowing the supersonic pill would have been easier.
Plus realistically, it's not like military planes are not allowed to fly supersonic over their own countries. Really, solutions, routes, compromises could have been found, it's just no one had the guts to.
When British Airways retired one of its Concorde to Seattle, it flew from New York / JFK to Seattle, it flew supersonic over Canada. Flight time: 3 hours and 55 minutes. Regular flight time is more like 5h30. Supersonic all the way would have been even quicker...
But supersonic transport could win for long-haul flights over ocean. Depending on the direction, SFO-TPE takes 11-14 hours. Going at mach 3 would cut that down to 4 or 5 hours. Airlines could charge significantly more for such speed. Faster trips also mean that each plane can make more trips per day. For a trans-pacific route, a 777 takes over 24 hours to go back-and-forth once. 300 passengers go west, 300 passengers go east. A mach 3 transport, even if it had half the capacity, could ferry more people in the same time period. If fuel costs were low enough (unlikely, I know), the supersonic craft could actually be more profitable than the 777.