Supersonic commercial flight is one of the most interesting. I think two strange things happened. First we got the internet - and mobile phones and video conferences and this has eroded the value of rapid physical presence. Second, and I think this is more important, people have become more willing to sacrifice their time for their career/money/firm/dream vs. family/happiness/now.

An acquaintance flew Concorde a lot in the 80's, the reason - "I could get to Heathrow in the morning, fly to New York, do a meeting, fly back and get home the next morning". Another friend is a exec at a bank now and goes on month long odysseys to the USA, Asia and Australia. The contrast in perspective and commitment is striking, I don't think that Concorde would matter at all to these folks.