It was cancelled because Boeing were late and over budget; by the time they started work on a prototype, Concorde was already being shown at airshows, and the US Senate voted to stop throwing more money at them. Sonic booms were at most one contributing factor among many to that senate vote.
Concorde was also late and over budget. And until Congress defunded the 2707, it had more pending orders from more airlines than Concorde did. Sonic booms weren’t the only reason for the cancellation but they were probably the single biggest reason.
Also, Concorde wasn’t even the first supersonic airliner—that was the Tupolev Tu-144.
