Curbside Recycling

I recently read a commentary that most recycling programs are a waste. Among the points noted were: no shortage of landfill space (another thousand years of garbage would only fill an area 35 miles square by 100 yards deep), double energy consumption and pollution (just preparing the recyclables can use as much energy and create as much waste as using virgin material), and cost (most recycling programs lose money).
All that having been said, the fact that something can be recycled doesn't mean it should be. Forget the esoteric arguments about externalities, finite resources, and so on--in the end recycling will (or won't) work because it is (or isn't) cheaper than throwing stuff away. This varies with the material being recycled. As a general proposition, any manufactured product that is (a) heavy or expensive in relation to its bulk, (b) homogeneous, and (c) easily separable from the waste stream by consumers can be recycled economically. Metals, notably steel and aluminum, are the obvious examples; both have high recycling rates. Surprisingly, so does newsprint. The poor candidates, at the moment, are plastics and mixed paper (including magazines). Plastics are too light and heterogeneous, while mixed paper contains too many contaminants. In the end we may conclude that this junk is best consigned to landfills. But given the advance of technology, who knows? We're in the midst of a great national experiment, and we'd be foolish at this stage to prejudge the results.