aluminum soda cans are a great example of standardized containers that work right now

The cans are almost never reused, instead they're recycled as the metal is too expensive to throw away and easier to render clean than almost every plastic.

It requires a lot of energy though to clean and melt. This recycling aluminum is not exactly green.

Recycling aluminum is very green when you compare the energy expenditure of recycling vs creating a net new can.

Did until recently- notice that you can now get regular Diet Coke (and I assume other sodas) in mini cans and the new Diet Coke flavors come in skinny/tall cans only.

It's a funny thing - manufacturers of products want to "stand out" from competition - so they use unique shaped containers for their products...

...the same is true for the container companies! The want to stand out from their competition - so they introduce new products (containers) with new shapes or sizes for that purpose.

While I am certain that some product manufacturers can dictate or have custom-shaped containers for their brand only, for many they just choose an off-the-shelf version and brand using labeling and/or color.

So - while going with standard-sized containers would be great for a whole host of reasons, for the product manufacturers - both for what is being contained, and the containers themselves - it presents a huge loss of profit and market share.

I'm not sure what we can do about this; it seems like something that would have to be dictated by government, because I doubt any of the other stakeholders (not even the consumers) will sway the decision toward standardized containers.

Soda cans (and for that matter, soup cans) are almost the only examples we have (ok - plastic milk jugs and paper milk cartons?), but as you have noticed, that's starting to fragment (it had already started with beer cans long before).

Of course a standard container would work just fine from the consumer's point of view and of course the companies will survive. The problem is for how long are they willing to delay this until losing the uniqueness of the shape is a better alternative to the social stigma attached to environmental carelessness.

And the Coke was just one example. A Google search for "iconic packaging" [0] will give you a lot of other examples of packaging so recognizable and unique that you can identify the product just by glancing at the shape.

[0] https://www.google.com/search?&q=iconic+packaging