From personal experience and observations it is clear that people are often left without a choice but to purchase/consume single use plastic. Someone will not decline a plastic fork if the only other alternative is using their hands, or when someone is really thirsty and they haven't brought their water bottle with them, the only solution there for them is to buy a single use plastic bottle.
What I have learned through my journey of improving my plastic consumption is that I need to be prepared to refuse plastic in many different ways.
I strategically purchased a (second hand) handbag that was big enough to carry my water bottle (which I resized to a 750ml as 1l or bigger was often too awkward to carry around). In my hand bag I always car a metal fork and metal straw so that I never have to accept the single-use-plastic alternatives.
These are simple preparations that I have been able to incorporate into my life so that I can easily refuse single use plastic.
But they would not have happened if I did not make the correlation between the size of my bag and the size of my bottle. This shows to me that we need to connect in more with the scenarios and causes of why people still use single use plastic even if they have alternatives. We need to create the infrastructure in our own daily lives to enable us to move beyond single use plastics.