Oil Companies Touted Recycling to Sell More Plastic
It is always a little surprising how naive people are when it comes to recycling. 
The majority of the cost and difficulty comes in sorting. Back in the good old days most US municipalities used to require people to sort their recycling by type, but over the years we have switched to a more wasteful system.For aluminum cans the material is valuable and relatively easy to sort. For plastic the material is cheap and sorting is hard (if you can't tell what the plastic container you threw in the bin is made out of (HDPE?) in a second then it is trash).FWIW this is also a relatively easy problem to fix. We could look to the brief but successful history of recycling in Taiwan as a good example to copy. (https://en.wikipedia.org/wiki/Recycling_in_Taiwan)