For the same reason why there is environmental regulation not just individual ethical choices of companies; Game theory. If those that make the "right" choices

For the same reason why there is environmental regulation not just individual ethical choices of companies; Game theory. If those that make the "right" choices bear the burden of those that make the "wrong" choices then this cost will accumulate and produce a power difference. If you already know this then why ask the question? If you dont then I can recommend you study some games https://en.wikipedia.org/wiki/List_of_games_in_game_theory https://en.wikipedia.org/wiki/List_of_games_in_game_theory