ZFT:
If some people are naive enough to believe that a B777 can be manually and normally flown without (AIMS) computers or the B787 can be manually flown without computers – dream on.
The issue is maintaining a good level of
scanning,
eye-hand co-ordination,
proper anticipation & "feel" of the airplane (responsiveness at differing weights, effect of changing wind components at various altitudes...). You can do this only with the A/P, A/T & F/D OFF.
Even though the 777 is also a FBW airplane, it won't prevent your from "over-banking" if your scanning has deteriorated greatly. Granted that this is a very extreme example, but the point is that what's important is the
human-brain-cognizance performance, not the electrical wiring or that "Windows" platform hiding behind the switch on the overhead panel. In this respect, i submit that you definitely do better at keeping yourself up-to-speed on Boeing FBW.