In our scenarios, the improvement of the world depends heavily on the use of reengineered waste/plastic. Some scenarios involved a wasteland, a completely undesirable place to live, and some involved a paradise, where everything is great.
The common denominator to all scenarios is reengineering waste.
The most probable future is continuation, where recycling and reusing plastic will become more common, but will not drastically change because the technology for plastic has not been the most advanced in the recent years. I think that the least probable situation is the limits and disciplines where recycling plastics become unsustainable because there are no resources for it. There is so much plastic in the world that it will take many many decades to get rid or / turn into something new.