Now imagine what the situation is like on an A350-1000 ULR. Impressive engineering, but much less efficient than shorter-range versions.
Something that blew my mind when I started flying jets; how much extra fuel we needed to burn to carry extra fuel. An increase in weight, including fuel, increases the fuel needed to fly it around. On my last relatively short flight an extra 10 minutes of fuel would have increased my burn by 200kg.