Geoffers: "the fact that there were two 'qualities of gear wheel out there"
Do you mean two different (conformal) Curvatures of Tapered roller bearing?
and
GreyHorizons: "How strong is rope when there is 1 strand, versus rope with multiple strands?"
I take your point about the spreading of load, but I'm not so sure it's as good an arguement as it sounds.
A bolt is (a bit) like a one strand cable. A rope made of strands, where every strand is near it limit, is obviously MORE dangerous, since the failure of any one strand will tip the others over their limit. OR imagine a rope where the failure of one strand leads to the failure of the whole crane. That is the parallel with this case.
The scaling point has some truth but the 400 single point failure items in a gearbox of this type should be taken seriously.