Over the Atlantic? Nah, the problem was it was very expensive and not a great experience for the people rich enough to afford it.

The US company trying to bring supersonic back are not only focussed on the flight speed, but also the entire customer experience.

Sure, the regulation that guarded against externalizing certain costs might well have been the only thing precluding profitability. Importantly it wasn't some shared cultural value leading to voluntarily leaving money on the table. Rather the regulator imposed it.

We are able to effectively regulate things like the operation of massive aircraft, eugenics, the dumping of toxic waste, or the refinement of nuclear material. But there are also plenty of things that we can't effectively regulate for purely practical reasons.