I am sure the 747 has fantastic redundancy. What those systems cannot legislate for is getting a lower cruising level then you planned for, subsequently resulting in not enough fuel to get you to where you want to get to. And then not being able to get as much fuel as you thought you could from one of your tanks, for whatever reason, resulting in an emergency being declared. I am sure the trend monitoring is great too - but what happens if it starts to paint an ugly picture halfway over the atlantic?
As soon as you start operating an aircraft in a non-standard way you run the risk of the unexpected happening. System redundancy does not give one carte blanche to press on regardless. For if the aeroplane does not do its best to ruin your day, then sure as hell, somebody or something else will.
Better to be down here wishing you was up there, then up there wishing you was down here.
Can you please answer my 'interview question' - it seems I have much to learn from somebody like you.