That cost is, depending on the market, about $80/tonne. Pricing in the cost of disposal would add about 0.04 cents to the cost of a plastic bag and 0.24 cents to the price of a large bottle of soda.
Plastic is not a problem. It has never been a problem and it never will be a problem. Eliminating plastic packaging is at best a complete waste of time and at worst totally counter-productive.
Climate change is a catastrophe; we have already passed the point of no return, and can now only choose how severe that catastrophe will be.
http://ec.europa.eu/environment/waste/studies/pdf/eucostwast...
https://www.environment.gov.au/system/files/resources/2e935b...
Why is there plastic in every corner of the planet[0]?
Why is there trash covered islands that humans don't live on and should be pristine[1]?
Maybe banning plastics is not the answer and responsible disposal is the correct answer, but there is currently a very large plastics problem that must be addressed.
[0]https://www.bbc.com/news/uk-scotland-glasgow-west-47947235
[1]https://www.forbes.com/sites/ericmack/2017/05/15/henderson-i...
People, in general, are bad at long term thinking, and they aren't going to pour hours of research into what type of packaging they are going to use. People also think that their singular actions are not going to have that much effect on the bigger picture. While this may be true, everyone cannot think this way.