[contravariant]

> Trouble is that, [...], even if they include the charging and refilling bits they can be cheap enough to throw away after use.

Well that is fixable, it's even one of the solutions posited here. Just make them artificially expensive by adding a deposit, which you'll get back when you return it to the shop (instead of throwing it away).

[bjackman]

But they don't need to be taken back anywhere. They are reusable. So this just ends up back at what I said about "taxing waste".