Concorde was only able to do supersonic speeds over the ocean. That seriously limits its viability.
Due to sonic booms which can damage buildings – particularly windows – and scare the wits out of the public. Likewise, airforce jets are not permitted to fly supersonically over land, except in times of emergency.
I have heard it wasn’t actually that comfortable either. Those with the money would probably rather spend it on a business or first class ticket on a traditional plane.
Reminds me of standard (cattle) class on Cross Country Voyager trains, which always give me back ache 
