> IOW, just like in the standard prisoner's dilemma, choosing to act is less about increasing your potential gains than it is about limiting your potential loss

> IOW, just like in the standard prisoner's dilemma, choosing to act is less about increasing your potential gains than it is about limiting your potential losses. You seem to be assuming that the potential gains are limited to current players of the game in this comparison. It's possible that Coke, Pepsi etc. are all losing more money on ads than they're gaining in market share against their current competitors and in increased sales. But that doesn't begin to address the question of whether advertising is a net loss. For one, the advertising also serves as a collective moat against new competitors, which could enter the market and eat up both Coke and Pepsi's market share. Maybe their biggest gain from it is that a bankrupt soda company from the 80s didn't replace them, and that a similar company today wouldn't have room to enter the market. It also doesn't account for more complex effects like a net increase in sales for all companies in that market. E.g. maybe Rolex, TAG Heuer etc. all benefit in the long term from expensive watches being seen as fashion accessories. If Rolex stopped their advertising spend one month and saw little immediate change, then TAG Heuer etc. might follow suit. But both might only experience the real loss years later as "luxury watches = must buy" faded from the psyche of their current and potential customers.