Youd think that faster flights,even if just as much fuel is burnt, for 100passengers instead of 400, that the maintenance costs would be similar.. and that the ticket price could be 4x the normal amount due to less passengers / flight..

Perhaps the mere fact that there was only ~7 or so of them, and theres thousands of normal 737s,airbuses etc,causes the per unit price to be high..so hard to recover R & D costs? hence super expensive tickets always..I guess the gov really has to invest into it to cause it to succeed.

There are other supersonic ideas around,and ramjets etc..
:o)