Potential and Value
The article only mentions it once. We live in an increasingly globalized world where our individuality can have an ever smaller impact on the enormous system. I think this drives a lot of people to have a feeling that they are living up to less than their potential and their value isn't that high. Maybe the whole system is living up to less than it's potential. But there is a lot of hopelessness about being able to influence it and our value within the system.
The reality is that much of what is horded has potential or is tied to something that had/has (like lost relatives mentioned in the article)
It seems like hording, like compulsive behaviors, allow us to create a small sense of agency in a world that constantly strips us of it and define potential and value by our own book.