system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What caused segregated recycling to disappear?

Growing up (90-2000s) all recycling was separated. Glass in one, cardboard in another, and aluminium in a third. I moved for uni and ever since I've only seen mixed recycle bins. What made this become the norm?
gpt
It's easier and more cost efficient to do the sorting at the recycling center.  You only need one collection vehicle with one single space, rather than devote space to each type.  Also, people who recycle are notoriously bad at separating things.