The engines were surprisingly inferior to what came just a few years later. Insofar, he is not completely wrong.
Yet they were the same ones Boeing was considering putting onto the 747-500/600, that's why the GE/PW project that led to GP7200 was formed in the first place, the A380 target emerged later. The difference was that Boeing looked at the market and looked at the engines and talked with customers and decided to not go forward. Chances are they wish they did not go forward with the 747-8 as well, so I think we can say the issue really is not the engines, it is that there really is not a big market for VLAs and that Airbus has so much zeal to build the world's largest airliner that they talked themselves into thinking there was a much bigger market for VLAs than actually existed.
The problem(s) with the A380 is/are very simple. Airbus severely misjudged the market and got itself caught up in an ego driven vanity project. No amount of engineering brilliance will ever be able to fix that it. From a technical perspective its a fine aircraft, its just too damn big. Leahy's ego simply cant accept that he was wrong.
Well, to be specific, we now have Jurgen Thomas saying it was too damn big, in the sense that it did not maintain efficiency as it scaled up so costly exotic materials (CFRP, titanium, etc) were needed to try to hit the targets they set based on efficient scaling.
"That was clearly a design-mistake that we have made."
The main design mistake they made was scaling-up a conventional tube-and-wings and expecting that to be enough to maintain an efficiency advantage.
That worked for the 747 because it introduced a second aisle, doubling capacity per unit of length, and higher-bypass engines. The A380 had neither of those advantages so of course it was quickly eclipsed.
It's pretty clear the 747 had far more efficient (if not reliable) engines compared to its competitors of the time, 707 and DC-8. This allowed them a degree of structural inefficiency (highly swept wings that favor speed over efficiency) that became more difficult to overcome as the airframe aged and new clean sheet airliners emerged. Yet their early thirst for fuel meant the 747 could carry enormous amounts of fuel, so as second (PW4000,CF6-80,Trent) and third (GEnX) rounds of engines were fitted the airplanes gained even more range.
Thomas points out the main deck is taller than a pax airliner would want due to cargo requirements. Leahy now agrees compromises were baked into the -800 to allow for -800F and -900. Leahy complains about needing to hit the QC2 standard, but it seems a clean sheet meant to be around for decades would need to do so.
Overall I find JL's comments to be a self serving distraction. It's pretty clear there was a huge amount of hype around A380 internally akin to what Richard Abulafia described as the 787's "drug like rush
", and JL was a very keen hype merchant back in the day. The engine thing is a convenient excuse/rationalization, the kind marketing guys are great at finding. He and Thomas are avoiding looking into the fundamental mistake: they made a plane far bigger than the market could support, and planned to make an even bigger follow-up. As I wrote in the earlier thread, I really wish Spaeth had explored this angle deeper with Thomas, and now I feel the same about Leahy. The mere fact he isn't pushing on this question suggests to me at least that it is a very sensitive subject that all involved prefer to avoid.