I could be wrong, but I was sure The Nomad or Mr. Peever had mentioned something a while back when AC 156 or similarly-timed flights switched from dinner to breakfast pre-arrival, and that only the omelette was offered.

With AC switching from a late-night dinner to a middle-of-the-night breakfast, I made the following assumptions/conclusions:

AC has data of exactly how many of those who fly on AC 156 etc were eating the dinner and the numbers were low relative to those who wanted to sleep.

OR

AC knows the omelette breakfast is "cheaper" food and decided to switch the meal.

Or all of the above.

On the multiple 156s I did a few months back, some pax wanted a meal, some wanted to sleep and some wanted snacks. The pax mix on this flight includes people on domestic tickets who perhaps were in the YVR MLL after 7:30 pm when all there was to eat were things like salsa, tortillas, cookies etc., as well as those connecting from some Asian flights who are on a different clock and wanted one versus the other.

If AC offered proper food that would qualify as dinner in the MLL, then those with access could eat there and not on the flight, preferring instead to try and get 3 hours and 47 minutes of sleep.

If AC had the ability to pre-order (and notwithstanding IRROPS and people who change flights), they would know which pax wanted a meal and what type.

BTW, I just did the 01:20 flight SIN-HKG on CX. It is a dinner service. Flight length is similar to YVR-YYZ, and there was also food available prior to arrival. As with AC, the crew do ask if you'd prefer dinner after departure, sleep, or your meal later in the flight closer to arrival.