How about replaceable, generic Li-ion cells?
I'd be more convinced about companies reducing the impact on the environment if they chose to use replacable and standardised Li-Ion cells in devices (there are some, but they are not widely used). As it is, as often as not, when a device is replaced then the internal batteries go too or, even where they are replaceable, such as many DSLRs or camcorders, you are faced with incompatible types, often chipped so you are locked into the equipment supplier.
With generic, replacable, cells we could all benefit from improved technology, just as we have with other formats. Li-Ion batteries all have similar electro-chemical charging characteristics (which is why you can get generic charges) and where chips are included to show remaining charge (rather than just as an anti-competitive measure) then standard interfaces could be produced. Of course there would have to be many more cell formats than there is for Ni-Mh due to the range of different device types now, but it would still be a tiny fraction of the number of proprietary formats out there.