They could ban plastic bottles completely tomorrow...and that would be a huge % dealt with.

There's nothing stopping that aside from inertia and vested plastic interests...because we have glass: which as all you old codgers will remember was what we used to bottle nearly 100% of liquid stuff in... until about forty or fifty years ago: back in those dark ages when we umm...recycled stuff...oh and we reused them too: milk, beers, lemonades...without melting down and reforming.

But naysayers will claim that transportation and cleaning costs for glass make it prohibitively expensive...well, we could afford to do it in the sixties & seventies in a less wealthy environment, so unsurprisingly I don't buy that argument.

There's just nothing to stop systemising returns efficiently in an economic manner...we have all the technology required.