The (very impressive) A380 will become the plane of choice for airlines like Singapore which need large capacity aircraft, and the 747 will begin to phase out of existence. But the 787 will probably be the aircraft of choice for most international routes in ten years - the A350 XWB being too late to market to pick up much market share unless Boeing falls way behind in their delivery timetable.
For a plane that’s “not selling”... it seems to be selling rather well. The 747-800 has 90 sales, 44 options, 15 additional purchase rights.
Not true. They've sold 90 firm orders, 44 options, and 15 purchase rights. The existing orders are probably enough for the 747-8 project to break even. Most of the 747-8 orders will be freighters. Probably no more than 100-200 will be passenger models. Even so, it is quite possible that the 747 will sell more than 2,000 units of all versions by the time the last one comes off the line.
The A380 won't sell many freighters, and the passenger market is fragmenting. People are trying to avoid the megahubs and fly more directly to their destinations on smaller planes like the 777, 767, and 787. According to Airbus, the A380 must sell at least 420 copies to break even. Of course this is just if no additional design costs for additional models are included. I wouldn't be surprised if the real breakeven number is 500 or greater. It took Boeing 12 years to build it's 500'th 747 and 24 years to build its 1000'th. I think all composite airliners will cut short the A380's life span. For most of the time the 747 has been on the market it was the longest ranged plane, and many airlines bought it for its range rather than its capacity. The 777-200ER and 777-300ER now both have slightly more range than the 747-400. It's little wonder that the 777 has been eating into the market that the 747 had all to itself. It's ludicrous for Airbus to think that current 747 operators will upgrade to the A380. Many are right sizing to the 777 or even the 787.