[mountn man]

The problem is airports.

You’re limited to near ocean airports, and strictly transoceanic routes.
The Concorde was limited to NY runs, from London or Paris.
They also made some runs down to the Bahamas

Make a supersonic aircraft, with a mitigated boom, and LA to NYC, SF to DC, CHI to anywhere, Or London to Hong Kong, etc, become a reality. Thus more aircraft built, more routes run and lower operational costs.

[BlueDragon]

The Concorde was limited to NY runs, from London or Paris.

It used to fly into DFW. International flights were allowed to go supersonic.

If memory serves, for a short time there was DFW to Dulles supersonic (along with a few other domestic flights at that speed) until domestic supersonic flights were barred by act of Congress.

Braniff partnering with British Airways...

There may have been a few Air France flights too.