It's too cheap when new, provides little value as a recycled product and is far easier than glass or metals to corrupt by getting contaminants in the batch. Con

It's too cheap when new, provides little value as a recycled product and is far easier than glass or metals to corrupt by getting contaminants in the batch. Contaminants could be as simple as a bottle of the wrong type of plastic or remnants of lid or labels. Better to discourage plastic use through an escalating tax, use home compostable alternative plastics and burn what is unavoidably produced in the local combined heat and power (that most places don't have). Of course it's still a hydrocarbon so ideally you want carbon capture and storage with that.