Food on board an airplane suffers from three issues. First, as has been mentioned, you're serving a large group of people. Banquets, wedding receptions, and other events at hotels experience the same issue--you can have steak or you can have chicken with maybe a pasta dish thrown in or even a fish dish. Second, have you checked the facilities where the food is served onboard a plane? I doubt a Michelin-starred chef could do but so much to prepare food for 10 people, much less 40-50 (we'll exclude WT and WT+ for this discussion) with limited space and cooking facilities as well as time. Third, the food has to be of a type that can preserve a reasonable amount of taste while being transported from the main preparation facility by trucks to airplanes before being served an hour or two into a flight.
Although I realize there are airlines that have a better reputation for food than BA, I keep in mind that no matter the airline I'm flying, they're serving me a semi-frozen food dinner at 30,000 feet.
The seat wins for me with a pleasant crew in second place. The alcohol can be important, but over the last several years, I've begun to understand that some of my biggest issues with what I thought was jet lag undoubtedly relate directly to the amount of alcohol I've consumed onboard so now I really care about how much water I can get to stay hydrated. Food is even behind IFE for me and even there, I'm not too demanding.