Not really surprising. Petro-plastic isn’t really recyclable. I’d rather they be incinerated than landfilled since they aren’t made of bioplastic.
The good news is that people are starting to get scared of microplastics showing up in their bodies. So we’re probably going to see paper, glass, and aluminum making a comeback.
A major part of the issue is contaminants: most consumer goods are very thin with lots of surface area, from dirty uses like food/drink handling. Lots of surface area for stuff to stick to, very little plastic recovered at the end of it.
I'd suggest that a seven stone sample isn't statistically significant but anyone will a spare airtag can replicate this test and share their observations publically.
I'd hazard a guess that we'd discover that the stores were not to blame, but then I'm cynical like that.
Think about it this way, many Starbucks are in strip malls or developments where they dont own the property. There is consolidated waste management for the site and the property manager handles it, its out of their control. This is 100% reality, my wife used to work in commercial real estate.
I think the problem comes in with the deceit. They have recycle bins even if they don't recycle and its out of their control. They're lying to the customer, that is the crux of the problem.