Or in other words, even with only 5 million people’s plastic in a rich liberal western democracy, you still can’t manage to recycle the vast majority of your plastic.

That 70% needs to go somewhere, and a landfill is the best place for it. Not an incinerator, a low income country, or the bottom of the ocean.

Or in yet other words, it takes time to change the habits of a thousand years.

None of it goes to a low income country, and very little to the ocean.

And our plastic waste per person is less than half of that of the US. Reducing plastic waste isn't merely a question of recycling, one must decide which plastics to allow for which purposes so that recycling can be effective. But not using it in the first place is the most effective.

And lastly what does the population of the country have to do with the problem? I this mentioned over and over again in various contexts.

Scale is a huge part of the current problem with global plastics recycling. There is only so much capacity at recyclers, and there is a massive global oversupply of material to be recycled at the moment. In recent history, much of this oversupply has ended up being shipped to recycling processors in lower income countries where much of it has ended up being dumped. This outcome is much worse for the world than putting it into a landfill in a high income country, despite being officially reported as "recycled".

Reducing the amount of plastic used is certainly a good goal, but it's a non-solution to the current problem. Non-recyclable plastics and the recyclable plastics which are destined to be mismanaged on a truck tomorrow are all better off in modern landfills.