These are some pretty broad generalizations...
First - and speaking only for myself - I did not "burn thousands of dollars on kits" that I never intended to build. Every single kit I've purchased (in excess of $6,000 total) I fully intend to build at some point in the future...whether I meet that goal is another matter.
Second, I think you could say that one who participates in any activity with some degree of regularity could be "addicted", in the strictest sense of the word. It doesn't matter whether someone golfs, fishes, or builds models nearly every day. You could call any of them "addicted" to their particular passion of choice. I personally wouldn't call them addicted since it tends to imply a physical or psychological illness. I think of them more as dedicated.
My personal story is probably not unique. Four years ago, when I got back into this hobby, I was still on active duty in the USAF and had a monthly "disposable" income in excess of $1,500. I could have literally burned $1,500 out of every paycheck and still had enough money left over to live on. However, I knew once I retired, my "disposable" income was going to drop to $150 a month or less. Because I wanted to build models throughout my retired years, I realized I would need to "stockpile" most of the tools, supplies, and kits ahead of time. Either that, or be extremely handcuffed by my soon-to-be "meager" income. So, while my income was more than sufficient, I stockpiled everything needed to allow me to build models once my income dropped. Now, the only things I need to buy on a regular basis are paint, glue, brushes, and other expendable items. I'll still pick up a kit every 3 or 4 months, but I don't "need" to buy any kits to keep me active in the hobby.
As I said in my first post, my primary reasons for keeping an inventory are for insurance purposes and so that I don't end up buying stuff I already have on-hand or don't need. If someone doesn't want to keep track of their supplies, that's perfectly fine by me. However, I also can completely understand why someone would feel the need to document their "stash".