> The problem is that it's so cheap to make new things that recycling is almost never cost effective. I think I lost faith in the concept (at least in the current economic climate) right about the time I found out that old glass isn't re-melted for use as new glass items, it's just smashed up and used as aggregate for road beds.
Yes, this is correct, although, it is also important to note that the reason why plastic is so "cheap" is because the externalities of it are not captured in the price. To put this in a different perspective, it is best to think of plastic as having a price that is below its costs. Plastic today has a low price. At the same time, the world is becoming filled with it. This accumulation is developing severe and systemic long term consequences. Reverting the damage is extremely difficult, expensive, and some damage may be irreversible, such as the loss of life and ecosystems. The externalities produced by plastics can be seen as a form of long term debt. In this way, it makes it clear that plastic is not all that cheap. In fact, it's quite expensive.
So how can we alter this behavior? I'll venture on my own here by suggesting a similar proposal by Professor Nordhaus and his book The Climate Casino, which is to capture the cost of the externalities into the price through the use of taxation. Carbon taxes is the most supported form of reducing carbon emissions by economists. I wouldn't be surprised if the same support exists for reducing our plastic production. If the production of plastic is taxed at the bottom of the supply chain, thus making it more costly compared to alternative materials, then we should expect an automatic market restructure that will naturally phase it out.