The problem is you don't pay for someone to separate your recyclables. If we were all charged for the garbage we generate, and also for how expensive it was to process, then it'd be fine. But in most cases, consumers in the US don't pay truly variable rates for the garbage they generate. (Even in the generally progressive San Francisco, you're charged a monthly fee based simply on how many trash cans you have - so pretty much everyone pays the same, and there's little incentive to generate less trash.)
https://www.recology.com/recology-san-francisco/rates/
However, in our current scheme (at least in the US), when you don't sort your garbage, the cost of that is mostly just distributed across everyone else - both in terms of the cost to process the garbage, as well as the environmental costs of things like improperly disposed of batteries that end up in landfills.
There's efforts to automate the processing of mixed-stream recycling, but they're not widely available yet.
It's entirely possible that we'll see single stream recycling end here in the US soon, because the places we used to send it for processing (like China) no longer want to do it for us due to the environment problems. At that point, we'll either have to start doing a better job separating it ourselves, charge more for garbage and single-stream so we can pay for processing, or fill up our landfills even faster.
Or we'll realize that it's not cost-effective to recycle anything other than glass and metal and stop subsidizing plastic recycling at all. Glass and metal recycling wouldn't be any problem for single stream recycling because the value of recycled materials would make up for the cost of separation.
If we're going to subsidize forms of recycling that aren't cost-effective, I'd rather we subsidize forms of recycling that also aren't annoying to the end user. Forcing people to separate Plastic #1 from Plastic #5 when it's cheaper to just dump both plastics in a landfill in the first place strikes me as Kafkaesque.
You can't base recycling decisions only on what's "cost effective" while not considering revising the fees people pay to dispose of household. Generating trash isn't supposed to be inherently costless, and it really shouldn't be.
Even glass has become questionable in terms of recycling economics[0] based on current fees, partially because Americans generally fail to clean the containers properly.
"It's cheaper to dump it in a landfill" is frankly, a lame approach that ignores the environmental costs and short-sightedness of creating more landfills. Do you want to live on a landfill, or next to one? They're basically a toxic waste dump.
The obvious answer is to do what other countries do: charge a lot for disposal of non-recycleable/non-compostable garbage, charge much less for recycling properly (and that includes cleaning and sorting), and use the fees from the garbage to subsidize the cost of recycling. This results in 1) less waste in landfills 2) more recycling 3) less pollution and 4) less use of non-renewable resources.
Doesn't this beget an economic feedback cycle? I.e., if it's more cost productive to send to a landfill, then more waste will be sent to a landfill, and so the costs to do so will go up as "demand" (waste) outstrips "supply" (landfill space). Then the cost effective pendulum swings back to recycling. Is that already happening?
In some ways, recycling should pay for itself. Consumers generate raw material for free, which through aggregation, sorting, and rectification (de-generating into raw-er materials) gains value for recyclers.
Depends how you define "cost productive". Cheaper on a cash basis, but that ignores the (not insignificant) externalities of doing that, such as landfill remediation down the road, and increased cost of transporting other trash to more distant landfill sites.
It's easy to say recycling should "pay for itself" but if you're going to do that, you need to consider the entire economic picture, not just how much value is generated from the recovered goods. There's also landfill savings, protection of the environment, reduced usage of energy (both in disposal and generation of new materials), etc. Given all of those, it can be entirely rational for a government to subsidize recycling heavily, because the overall impact is still "cost effective."
However, in our current scheme (at least in the US), when you don't sort your garbage, the cost of that is mostly just distributed across everyone else - both in terms of the cost to process the garbage, as well as the environmental costs of things like improperly disposed of batteries that end up in landfills.
There's efforts to automate the processing of mixed-stream recycling, but they're not widely available yet.
It's entirely possible that we'll see single stream recycling end here in the US soon, because the places we used to send it for processing (like China) no longer want to do it for us due to the environment problems. At that point, we'll either have to start doing a better job separating it ourselves, charge more for garbage and single-stream so we can pay for processing, or fill up our landfills even faster.