And it was very expensive because it was a Cold War prestige project. A three-way race between the US, Europe and the Soviet Union. Just like the Apollo program it was forced into existence through force of will, on a tight deadline with limited economic considerations.

If anything it's a miracle how practical the Concorde was and how long it remained in operation

That was why it was done at all, but not why it was expensive.

At that time, maybe yes. These days, it would fail in many other criteria. Sound pollution is brutal, can't be effectively mitigated and it was all just about rich sparing few hours to get to NY/Paris faster.

Fuck the rich, take normal airliner like everybody else if you are so poor to not have your own jet. We are not bending health standards to whims of few moderately wealthy individuals, sounds like some societal progress there.

A sort of self-regulating issue for a change.

It was expensive because they only built 14 aircraft (plus 6 prototypes).

And the overflight bans were a large part of the reason for all the sales to fall though. If the development/maintenance costs had been split over hundreds of craft as planned, they would have been much cheaper to both buy and maintain.

There is still the issue of high fuel costs, but fun fact, most of the cancellations came in months before the 1973 oil crisis.

The most important datum is that Boeing refused to build an SST without large government subsidy. This was evidence they decided there wasn't much of a market. And this decision was taken before the 1973 mideast war that kicked off the oil embargo and energy crisis.

Today, we see similar evidence in that Boom is being forced to develop their own engine because none of the actual engine makers want to make an engine suitable for a SST. I believe there is considerable skepticism that Boom will be able to do this, btw.

It should be noted that even subsonic airliners have gotten a bit slower over time. Fuel economy > travel time for them to some extent, even being subsonic.

The SST project was basically a government project. They even had both Boeing, Lockheed and North American submitting competing design proposals.

They were also originally targeting the transcontinental market, so it would have exclusively flown over land, so the sonic boom issue was way more devastating.

They actually ran tests, flying supersonic military aircraft over Oklahoma City for months to see how regular supersonic booms would affect the public.

The public outcry was a large part of the reason why congress cancelled the SST project in 1971, long before 1973. They then immediately introduced the supersonic overflight ban to hinder operation of Concorde.

There was also concern that the NOx produced in the stratosphere would affect the ozone layer. This was about the time concern about the ozone layer was ramping up.

That's Occam's razor more or less.