Lufthansa Flys the A340-600 to DIA in the summer and the 747-400 in the winter these are 2 of the biggest aircraft in the Lufthansa fleet. Why wouldn’t they send in an A380?
If they can’t even fill a 744 year-round they don’t need the capacity.
On a route where you mix 300 and 375 seat aircraft, why would you swap in a 525 seat aircraft?
I’m not 100% sure how full the flights are. I have heard that British Airways is only filling about 60% of their 777-200 they send in here to Denver.