lives that they are filling with all that stuff. Getting rid of the stuff would mean having to face that underlying emotional pain. That's why they can't do it. Their behavior really isn't about the stuff at all. It is not a healthy way to deal with their issues (obviously), but they found that it works, so that's what they go with.
That's probably better than abusing alcohol or drugs, I guess (although sometimes that isn't clear). But a much better and healthier solution would be to get counseling and actually address the underlying issues.