I'd say it depends on the time of day. I recently had two of those long domestic flights (EWR-LAS,LAS-EWR)

On the outbound flight, which was to leave at 7:15 pm (but which left at 10pm ) they served a warm sandwich, on the eastbound flight from LAS (early morning at 6:45am) they served a bowl of cereal.

I wish they'd serve the carrots again