Yeah! I noticed it too that shorter flights have a more substantial breakfast than their longest SFO flight. It is even more bizarre because from a competition POV, TPAC tends to have airlines that are more likely to serve large meals compared to TATL competitors.

I have never seen yogurt served on its flights to/from Asia. My theory behind the lack of yogurts/fruit is

1) They do not have enough chiller space to be storing yogurts for all passengers on long haul flights to/from Asia as they have to store other service items that require chillers. However, I noticed on UA 1 the passengers next to me with a special meal got a yogurt on their meal tray (with bread, fruits, and a hot item)

2) Budget - the longer TPAC meals have a mid flight snack bag and that probably used up the budget to serve yoghurts/fruits. I also noticed that when they add the muffin into the snackbag they do not serve fruits on the breakfast tray (and vice versa). UA might have a similar meal budget on TPAC and TATL flights to/from SFO so to serve a snack bag they need to cut back in other areas. It is interesting that UA does a snack bag service because none of the Asian airlines I know that I fly on conduct a snack service so it is a nice touch. However, I suspect the snack service does require UA to cut back its budget on the two main meals.