Aviation is a lot less glamorous then the days when Concorde was envisaged. We've gone from expensive, luxury to mass market and that has entitled a huge switch towards ultra efficiency both environmentally and economically.
The other aspect has been post 9/11 security. No matter what you do, you seem to end up taking hours and hours to get to a flight these days. So whether your aircraft shaves a few hours off the journey starts to become less relevant.
Extra security has decimated the use of short regional fights too. Often even though the flight night only take 35 minutes, you would still be quicker driving due to all the rigmarole at even very small airports.
If we want to see supersonic passenger flight again, it's going to have to somehow archive ultra efficiency. That's a huge engineering challenge.