The technology for Concorde is still around. What disappeared is the economic case for it. (One might argue that the economic case never existed, or disappeared before it even started flying.) If aliens showed up tomorrow and said they would enslave the human race unless we built a Concorde-level airliner, we'd have no major trouble getting it done.

> Not so sure about it. Look at Concorde.

The absence of a business case is not the same as the absence of technology.

Technology for supersonic aircraft has moved forward since the Concorde. Economically viable applications for that technology for commercial passenger transport have not, however, appeared. (Or, if they have, they haven't been recognized.)

Even if there is an economic case for supersonic civil aviation, considerable environmental problems must first be overcome.

Given their extreme noise, pollution, and ozone layer disruption it's certainly a good thing there aren't hundreds or thousands of Concorde-equivalents plying the skies today.

Concorde may have failed but jet travel is far more common and affordable today than when it was rolled out.

Because technology is in service of individual and consumer needs. If there isn't a sustainable business model for supersonic passenger flight then it doesn't exist. And, frankly, it's not up to government to provide that.

Technology is both economics and engineering. Just because something can be done, doesn't mean it should be done if no one is willing to cover the costs.

There is another thesis that technology no longer disappears anymore. It will remain in some dormant form. Some crazy hobbyist group in the US, Europe, or Japan will lovingly curate it. Even now, I think you can charter the operation of a restored supersonic aircraft, if you have enough cash. Not sure if any have an extra seat for a passenger, though.