it's not exactly unreasonable to assume that some flight crews might have a bad day if all the displays blank while doing a CAT III landing under extremely challenging conditions
Actually, that’s probably one of the less problematic scenarios. The autopilot(s) will be engaged, so whether the display units are functioning correctly or not has no bearing on the flight path of the aircraft.
Even if you lost all the EFIS on rotation, you could engage the autopilot and fly the aeroplane through the MCP and CDUs. It’s unlikely that you’d lose the standby instruments, which are quite different to the primary ones and mostly self-contained.
I’ve got >10,000hrs on the 777 and have never experienced nor heard of anything like this happening. I have had a few DU failures but given the redundancy available, this is a non-issue. Obviously, spending a lot of time sitting in front of them at night/IMC, I’d like the displays to be as hardened as possible to any interference but it does seem to be a chain of “what if?” down to ridiculously low probabilities...