The entire pricing model of airplane tickets has changed dramatically in thirty years. People seem completely unwilling to pay a premium for anything. It's as if they'd gladly give up another three inches of legroom for another $40 savings.
The economic conditions were created by airlines mismanaging expectations.
While that's certainly true, I often wonder what would have happened if super-sonic development continued. Certainly, at my income level, I would never pay for a Concorde ticket.
But, if it were $800 vs $1200 for a 9-hour vs 4-hour flight (and all else equal), I might be tempted. That would allow a very early departure from DC and still be in Rome for lunch. Currently, the best option is usually an overnight flight, but I never sleep well on those.
An AM supersonic flight from the US east coast to western Europe gets you in around dinnertime. As I recall, that was what the Concorde did to London from NYC. My dad told me once after he got upgraded to the Concorde from the 747 he was on that he didn't care all that much for it because, rather than having a nice first class dinner on the plane, he was arriving in London at rush hour :-)
The economic conditions were created by airlines mismanaging expectations.