What might the business model be for a hypersonic jet?
Well it’s cool but it’s nothing new.  Hypersonic transports and runway to orbit vehicles have been proposed since the late 1970s but never materialized into flyable hardware for a number of reasons, mainly engineers have not been able to solve the technical challenges associated with structures, propulsion, mission profiles, heat transfer and protection, operating costs for skittish airline operators, etc.

The new Boeing hypersonic transport may be the quantum leap forward for air and space travel but it could easily join the heap of fantastic ‘paper airplanes’ that never flew or possibly flew as clandestine prototypes such as:


Rockwell National Aerospace Plane - “Orient Express” from Reagan’s
1986 State of the Union Address. 
Lockheed SR-91 “Aurora” reconnaissance aircraft. 
High Speed Civil Transport concept from the
1990s 
Lockheed Martin X-33 / VentureStar SSTO concept 
German Sänger concept aircraft 
Lockheed SR-72 Spy plane of the 2010s


As far as the passenger world is concerned, the big market are the transpacific routes, where the high-speed would make a major difference in travel times for both the public as well as business travel. If you could design a hypersonic aircraft that has a 6000 - 7000 mile range with operating costs in the neighborhood of 30 to 40% higher than existing subsonic airframes, you would have a game changer. But that’s always been the challenge.

Who knows, maybe the technology now exists to attempt a successful hypersonic manned aircraft.  I for one would welcome it as I find current aircraft are becoming insufferably boring.  OEMs churn out one bland subsonic twin jet after another, just wringing a few more knots out of a few less gallons of gas with new avionics etc.  I was supposed to be living on one of those cool Gerry O’Neill space colonies at this point!