john, i know what you want to say and you are of course right, which is the main reason why my outfit still requires its pilots to use raw data manual flight as often as practicable in normal line operation.
However the example you used was pretty much the design standard for fail operational airplanes, and even the old fashioned 737 can cope on its own with any single failure during automatic approach and happily continue with its automatic landing and rollout. And raw data manual flight very close to the ground in 75m RVR weather is something i rather avoid.
Don't get me wrong, we have to demonstrate every six months we can do the usual manual flight OEI go-around and approach, and i would love to have the requirement back to do it raw data as well. However the last part was removed around 2 years ago after some regulator intervention that that isn't necessary and a too high failure rate would cost the TREs license.