> A system where humans split garbage from recycling, and then potential split recycling into e.g. corrugated cardboard, glass and everything else can work just fine.

If it's done perfectly every single time - sure. But these are humans we're discussing...

It's silly to even have to think about if something can be recycled or not. Gotta look for that recycle number on the package first - ah, this seemingly regular plastic bottle cannot be recycled after all! Pizza box with a small amount of oil stain? Nope, can't recycle that either.

Sorting machines are clearly the only reliable way to manage waste. Everything else is a distraction meant to make you feel good about doing your part, even though the reality is you probably did some of it wrong and half of the stuff won't be recycled anyway.

You really do not want to mix garbage and (potential) recycling.

Fine, throw anything remotely potentially recyclable together (and have it post-sorted), but not cooking fat, diapers, dog shit, and more.

So dry and wet garbage?

The problem is 90% of proper will think that a grease stained pizza box is dry.

I agree. Any system that requires cooperative, collective action from un-incentivized humans is doomed. All you need are a significant number of uncooperative and/or antagonistic people, and the system will fail. A lot of people are just apathetic and will toss their junk into whatever bin is closest, regardless of what's supposed to be in it. Also, there are a fair number of people who will go out of their way to put things in the wrong bin. I knew someone who proudly admitted he would dump old rotten eggs, motor oil, and poo into his recycling bin because "Recycling is authoritarian government overreach by the liberals." You just can't have nice things, because of people.

Look at how every country's COVID strategy depended on cooperative, altruistic, collective action from ordinary people. This strategy failed everywhere it was tried.

Majority of the stuff you place in the recycling bin cannot be recycled, or will not be recycled - despite good intentions and attitude.

Humans are fallible, and make mistakes. Humans also have more important things to worry about than what can or cannot be recycled (the reality shocks most people).

It must be automated if it is important enough to do at all. It has nothing to do with cooperation, altruism, collective action or whatever.

Most recycling facilities already sort everything with better success than 99% of humans can.

And also like you said, most things are not commercially viable to recycle, so a lot of things people put in blue bins ends up in landfills anyway.

Humans should only be used for a very rough split of garbage - e.g. separate yard waste from other trash, and that's it.