Solid is heavy. Liquid is lighter. Gas is lightest.

Solid is barely profitable. Liquid is fairly profitable. Gas is highly profitable.

Restaurants, which serve food, only make money on drinks.

Liquids can be profitable, even without a secret formula. Bottled water is more profitable than running a restaurant.

But even more so than liquids, gases are the most profitable. Cigarettes and the like. You could serve marujuana in brownies, but it more profitable to sell it as a smokeable thing.

The reason for this is that solids satisfy demand more than liquids or gases.

If I’m hungry and I eat a certain amount, I’m full. I may eat dessert, but I’ll forgo further opportunities to eat in the near term.

If I’m thirsty and I drink, I’ll quench my thirst after a certain amount. But if I urinate, then I’ll be able to drink more. This is especially true for alcoholic drinks, which is probably why they have higher margins than soda.

But if I’m smoking cigarettes, I have a very high limit on how many I can smoke within a few hours. Several packs are possible.

This pattern can likely be generalized beyond consumables.