Horders live powerless lives. It's rare that you seen an insanely wealthy person who built their own business who hoards things. Usually, hoarders have had either an emotional abuse component growing up or emotional trauma as an adult.
What's money equal? Power. Hoarders with a few dollars in their pocket will seek out that next high that they get from purchasing an item that they MIGHT use some day. From the time they put that item in their cart until the time that they make the purchase, THEY are in control of the decision making process. It might be the only time they ever feel in control of their own lives, as the mounds of stuff close them in and hamper their movement.
I see hoarding as sort of a sister to people who have issues with overeating, especially those who were conditioned to "clean your plate." The compulsion to eat until past full because you've got a food opportunity that you must not squander is probably a decent part of the reason that we have as many overweight people as we do. It's not enough to sit, have a nice dinner and some conversation, and let the food settle while you eat, discarding a bit if you get full. For some families, you are expected to consume every speck of food lest it go to waste. This ends with people feeling that they are satiated only when they are stuffed because they have been conditioned to behave in that manner.