>>105340273Broths are cooked, are meant to be served hot, and has to feature a stock. Cereal, both before and after milk, only SOMETIMES has that first quality.
Before milk, the vast majority of modern (read: anything Kelloggs peddles) cereals is technically a candy, featuring lots of sugar and with the main draw-factor being tastes and colours.
Post-milk, cereal is neither stew, broth or sauce. It lacks the heat and use of stocks for the first two, and is not meant to add flavor to anything, which is the hallmark of sauces. Even the milk alone is not a sauce. Alone, milk is a beverage. It undergoes a brief transition through the sauce state as it is applied to cereal, but is quickly disqualified as its surpasses the cereal in mass and volume. Ketchup spread over a steak is acting as a sauce. A bowl of ketchup with chunks of steak in it is no longer acting as a sauce (merely an abomination).
The answer is found in recognizing that cereals dissolve in milk. Cereal+milk is a solution, albiet one still undergoing the process of dissolving.
Cereal is a (or perhaps, THE) Solution.