cxorcist,
1) The Boeing website numbers assume the 747-8I has 467 passengers onboard and assumes the A380 is 10t heavier than it is. 747-8I website numbers assume that airlines have a first class with a 152 cm seat pitch, and 96 cm seat pitch in business (Cathay has a 205 cm bed in first, and a 198 cm bed in business, the actual pitch is even higher). The seat width Boeing uses in first is 53 cm, and 50 cm in business, Cathay provides 91 cm in first, and 81 cm in business. In real airline configurations the number is approximately 80% of the capacity Boeing is claiming (as a comparison Boeing claim the 777-300ER is a 370 seat 3 class aircraft whilst Cathay has 301 seats, again around 80%). In comparison the A380 is touted as a 525 seat aircraft, Lufthansa has 526 seats, Air France 538, Singapore 471, Emirates 489, and Qantas 450 (they have a 4 class configuration).
2) The A380 cargo space compared to a 777-300ER is not as good (38 vs 44 LD3s), but it is better than a 744 (38 vs 32 LD3s). FYI the 333 and 772 have the same LD3 capacity as the 744. It is more expensive to lift freight underfloor on a passenger aircraft than it is to put in on a dedicated freighter, the freight you want underfloor on passenger aircraft is high yield freight, not general freight.
3) Qantas is not having any range/load difficulties with the A380. The aircraft is often dispatched 20t below MTOW with full a payload even on LAX-MEL. Qantas has had a medical diversion into Fiji, and severe weather in SYD also caused a tech stop in Noumea. The 744ER that Qantas operates only has a capacity of 26 LD3 as the space of 6 LD3s is taken up with additional fuel tanks.
4) The 747-8 does not have a lot of commonality with the 744/F outside of the cockpit, parts wise is it upwards of 85% different.
5) SQ/QF/EK A380s during the recent GFC had load factors were on average 5 points higher than their other long haul aircraft. It allowed SQ to consolidate the number of services whilst still retaining capacity, they also charged passengers a premium to travel on the A380.
6) The cabin altitude (around 6000 ft) in the A330/A340/A380 is already what Boeing is planning to bring in on the 787. It is nothing new. The upper deck and forward section of the 747 are difficult to adapt seats for that were designed for cabins with parallel walls like the 777.
7) Cathay is the largest A330 operator in the world, and operates the most Airbus types either directly or through its subsidiaries. The A340-600 did the job it was intended for, it opened up the direct HKG-JFK route thereby linking up the three main financial centres with non-stop flights. All the carriers that are operating the A380 have stated that their aircraft are exceeding the performance guarantees.