Wouldn't plasma gassification be a much better way to recycle plastic? In theory it might even give a way to recycle some of the metal that makes its way there.
https://en.wikipedia.org/wiki/Waste_hierarchy
You can extract metals from the ashes as you mention.
For regularly used things like drink containers it's not quite as good as recycling them though.
And as more renewables enter the grid, theres less fossil fuel to displace but if the RDF (resource derived fuel) can be stored then it acts as a kind of storage.