I am not giving up on the A380 yet! :) While it might be more profitable for the airlines to use the large 2-engined planes on more direct routes, air traffic is still increasing. Yet, most international airports already are operating at their capacity. So I wonder when the point is reached, where it is no longer possible to add more flights to increase the passenger count. Then, larger airplanes would be needed.
At that point the A380 will be a 30-40 year old design, and won't be competitive anymore.
Also, the shift to point-to-point can only grow so much before the fuel efficiencies of the 787 and A350 come into equilibrium with the density of the A380. Moreover, most of the world continues to flock to mega cities. As cities expand airport usage increases while simultaneously making it more costly to expand or build airports.
But 20 years, let alone 40 years, is a long ways out; who knows what will transpire. That said, the 777 is 25 years old and still dominating. At 30 and 35 years it still may be dominating even as the 777X slowly replaces it. A 30-year-old A380 may still be no less relevant, if not more relevant, than today.