EEngr
All major aircraft manufacturers publish comprehensive market forecasts, looking at a period of at least 20 years. Not one thinks there's a big enough market for an SST.
These guys are not stupid and would not want to miss out on a juicy new market segment (as the US initially failed to see the domination of the widebody market by twins).
Many things have changed since Concorde was developed. Today probably less than 1% of business travellers can elect to pay more: travel budgets are tightly controlled and firms negotiate bulk fares with airlines.
So the customer base comes down to a few corporate chiefs and a few seriously rich individuals. Not a base for launching a (my guess) $30b development programme. That's a non-recurring cost of $150m per plane over say 200 units.