If you look up the fares on any of the ticketing sites like kayak or expedia it shows that while Cathay charges similarly to BA on LHR-HKG-LHR routes, all of the other carriers offer radically reduced fares due to having to make connections. Also, keep in mind that it is the total system revenue that is taken into account versus only the sector by sector view. This means that one pax traveling to HKG as a final destination may be worth more than one who is connecting to DPS. Nonetheless, the amount of competition of lower fares for the mainland carriers is quite fierce; therefore, simply raising the fares won't do anything but exacerbate the revenue issue.
There is a fundamental problem that CX faces, but it won't be solved by an a-380 or by slightly raising fares. Let me clarify that last part: you cannot just raise fares with such high competition without doing something to the product. The a-380 would be a change to the product, but due to its high operating cost the resulting rise in revenue would be offset.
But I have been wrong before.