The beauty of the jet pump operation is that it uses venturi pressure from the high pressure fuel coming from the engine (low volume) to draw or suck the fuel at low pressure (high volume) back to the engine with no moving parts. Very reliable operation with an electric standby pump in case the system fails, which might be due to a foreign object blocking the venturi inside the jet pump. Also, the standby pump is used for engine start and crossfeed or crossflow into the other engine/tank.
Should the high pressure pump within the engine fail, then there is no way that the engine can sustain itself (according to ground school) nor there is enough pressure from the standby pump to keep it running.
This system has been in Lear's since the old 23, through the 30 series, 50 series and 40, 60 series.