Why do people acquire more than they need to live?
The issue of how much is necessary to live a sustainable and satisfactory life depends on the definition you choose.
The communist definition of necessity led to many poor citizens, because it disregarded the need for people to actualize themselves. In the absence of this possibility, people cannot live a fulfilling life, as they work a lot and receive little pay, since taxes are very high in a communist society. This makes life in a communist state very difficult for many.
This is why I always include self-actualization when I write about necessity. However, the issue of self-actualization largely depends on what you like to do in life, whether it's in work or in your free time or both. Because the issue of self-actualization is generally vague and depends on the individual's preferences, it's difficult to generally determine how much is necessary to have on a universal scale.
Some people may disagree with me, and that's okay, but I view the printing of my books as necessary for my needs of self-actualization. Some people, who have different skills and preferences than me, may find their necessary satisfaction in life in other fields of purchasing, which may or may not be cheaper than the annual printing of my books.
This is why it would be technically difficult to answer the question of the first paragraph, because when it comes to self-actualization, there may be people who say that their purchases are necessary for this need, and some people may be self-deceived into thinking that this is the case, when in reality it's nothing more than an addiction.
So, the result of all I have written here is that people may acquire more than they need for two primary reasons:
They are either addicted and they know it.
They believe that their acquisition is important to their self-actualization need, but are in fact deluded by their own thinking.
To determine whether or not the acquisition is indeed for self-actualization, I suggest trying to set a period where you won't buy these designated products at all, and then see how you cope in their absence.
If you can manage to do without these products on this extensive period of trial, then you will be able to know that you are indeed not addicted to these products whatsoever. If, however, the opposite results arrive, then you might be addicted and not just doing so for your self-actualization.