They can burn the plastic along with some paper, generate electricity from the energy released, use the electricity to power smokeless burning technology that captures the CO2 and other pollutants before they are released released into the atmosphere. But you are right. If you are going to collect all that plastic, it is more economical to simply mix it with asphalt and use it as paving material. Fact is recycling plastic is a fool’s errand.
100% same stuff different form