You're certainly correct, a solution does not require a benefit to the manufacturer. I suppose I was thinking about it from more of a laissez-faire point of view - that is essentially, how can we have our cake and eat it too (or in this case, our cheap soda)?

If the government passed laws/regulation that mandated certain packaging requirements for companies like Coca Cola, that would be a top-down solution and Coca Cola would have to comply, lest they wish to face steep fines and litigation.

In regards to soda, you're right - consumption taxes have proven effective. I believe cigarette taxes have proven effective in the same way. But an environmentally effective top-down solution would of course apply to many more consumables that just soda, sugar cakes and other generally unhealthy items. It's possible that top down regulation could push costs higher for smaller companies that offer healthy options in environmentally unfriendly packages. If costs are too high for smaller companies like these, then there may be fewer healthy alternative options (because we know Little Debbie and Coca Cola aren't going anywhere, regulations or not). This is obviously a very generalized example - in reality, many of the healthy/organic foods items already come in environmentally-friendly packaging.