That is IMO speculative. AFAIK LH is keeping their 747-8 for the foreseeable time. I doubt that they'll order any additional ones. The next generation of the 777 and the larger versions of the A350 are getting so large that they are in direct competition with the 747-8. The A380 could be made more efficient if it was extended (something Emirates wanted for years). It would bring down cost per seat but it's a huge gamble for Airbus: Few airlines require that massive airplanes (cf. most airlines waste space on the A380-800) and most would probably prefer adding rotations giving more flexibility (in case of light loads they can just cancel one flight; passenger potentially get better connections).