Your point is well made. Except your statement that airmanship is a strenuous mental task. Presumably, you jest of course? But the design of the PFD in sophisticated aircraft is such that all the information needed to fly the aircraft on instruments is in the PFD. Combined with that information being fed into flight directors, in theory anyway, the instrument scan can be reduced to one flight instrument - and that is the PFD.
This has always been the problem when for regulatory reasons raw data is required to be tested during proficiency instrument rating tests. Pilots who are rusty at raw data instrument flying are like this because most of their flying on jet transports is gazing at the PFD with tunnel-vision.
Most PFD have a ground-speed read out and it should not exactly overload the crew to note that figure during the 80 knot call-out which is done from the IAS in the PFD anyway.