You forgot the part of shaping public opinion that their products are not a health issue and having the public subsidize their main ingredient. Even if you don't drink soft drinks you still subsidize health effects and corn and sugar.

The same applies to drug dealers. Busybodies notwithstanding.

But underneath that simplistic surface view, you're dealing with somebody who inflicts cost on society as a whole to extract profit for themselves. And they extract it in a way that individuals don't necessarily care to fix.

And so, you'll need somebody to stand up for a functioning society. That would then be your "busybodies". (Sure, there's the libertarian fantasy of complete self-determination. Which inevitably leads to a might-makes-right world. Most of us have decided long ago we'd rather live in a civilized society)

If soft drink mfgs had to actually pay for the water, sugar, pollution, and diabetes treatments, they wouldn't be profitable.

Externalize costs, privatize profits.

A methamphetamine dealers profit comes from making something their customers like and want to pay for... etc.