Supersonic flow...
The Concorde aerodynamicist was Prof Ted Talbot, he was indeed the leading light in the design and refinement of the engine inlets that made the supersonic cruise possible.
The B-1A inlets were angled in 2 axes whereas on Concorde the angling was in 1 axis only. That made the difference in terms of finding a workable solution to the problem. The B-1B inlets were redesigned to hide the engine compressor faces from radar so there was some advantage to the difficulty of getting the original inlet configuration to work.