1) The flight markets are different now. There's been a large increase in both transatlantic and transpacific flights, especially the latter. These change the economics of considering only these types of flights, flying only over uninhabited regions.

2) The technology has changed. We're much better at dealing with sonic booms now. You can't get rid of them entirely, but you can reshape them. You can't send everything "up" but the longer of a tail you can make the more the sound dissipates by the time it hits the ground. There's lots of research around this and as you can imagine, incredibly important for the military. You can't fly fast spy aircraft if they are just announcing their position while flying around. Sure, there are satellites, but those are predictable by the enemy, you'll always need aircraft to do this.

However, there are markets where you don't have to fly supersonic over land, the distance is long enough for the speed to matter, and there is massive amount of demand. The only problem is, such markets require a longer range than what the Concorde was capable of. Notably, all the very frequently traveled trips over the Pacific.

Concorde’s sonic boom was astonishingly loud. The night flights would go supersonic outside the Bristol Channel at around 9pm to 10pm. It was still audible over 60 miles away and sounded like a muffled barn door slamming outside.

Far louder though — it would wake all the pheasants up just as they’d gone to roost.

England in the '80s didn't give a shit about little people. Had it been really profitable, Concorde would have continued operations. It just did not make sense economically, particularly once they stopped making new airframes.

It failed because the market dried up due to economic reasons, and they couldn't fill seats.