[ZeroGravitas]

Yep, which EPR covers.

For example, British milk sellers mostly use the same shared milk container, with different labels.

They figured out how to lower the cost, because they were paying for it. They get really in depth in the specific amounts of dye to use in lids etc. to maximise recycling.

https://wrap.org.uk/resources/report/hdpe-milk-bottle-resear...

None of that needed specific regulations, just assigning the costs to the people responsible.

[Schroedingersat]

There's still inertia and favouring of status quo even in that example.

Milk bags have been in use in some places for decades, pack better, are lighter and use less plastic than a bottle lid. Other places do not use them for no particular reason.

[ZeroGravitas]

I'm not promising immediate perfection, just economic incentives that point in that direction, rather than 180° opppsite.