I wonder if it's the same thing that happens on a personal level in other countries, just happening on a more macro scale.
Thinking about my own life, when I moved to university all my possessions fitted in a car with both me and my mum as well. I was happy. After university, I went travelled for a year and all my possessions fitted inside an 80L rucksack. I was happy.
I came back to my own country. Got a job. Got money. Started buying toys because I could, but everything still fitted into my room in a shared house (plus a few things in the common rooms).
5 years later, I bought a house and all my possessions fitted in 2 car loads, but this time with just me driving. But then, I wanted furniture, so I got a load of big bulky things delivered. And over the years, I've been buying more and more things and never really felt like I needed to throw anything away because I had lots of space.
Now, if I do the exercise in the article, I agree. Everything I can see is stuff I wanted. I might not have used it for 10 years, but it's still in good condition, I still have the purpose in mind that I bought it for, and it's wasteful to just throw away. But despite that, it makes me sad because it's just clutter. Every I look in my house, it's just stuff, most of which I don't really need and haven't used in years, but... I might. Just today, there was an article about Kobos, and I dug out my 3 Kobo's that have been untouched for years. Would I have been sad if I'd thrown them out and couldn't now use them? I'm not sure. When I go travelling for a month or more at a time and only use half of the things in my suitcase, I kind of wonder what the purpose of everything else in my house is.
Anyway, that was long and rambling, but my point is just that as we get older and have more capacity, we naturally want to buy nice things that we want in the moment. I have had times in my life when money was scarce (for my family in childhood and also when I was out of work for about 3 months during the financial crisis), and so the urge to keep things that are in good condition is very strong. If I fall on hard times again, I could still use them.
If you look at society as a whole in China and Taiwan, you see a place where the vast majority of the population were poor if their lifetimes. I remember reading an article once about how the average family in 1980s Beijing would aspire to own (not even own, just aspire) a family bicycle, a watch and a radio. Compared to the West, their lives were incredibly frugal, not out of choice, but out of necessity. As their society's standards of living and purchasing power has rocketed over the last few decades, people are obviously able to buy more, but the older generation will always remember the hard times. Changing your scarcity mindset is incredibly difficult - I've wanted to declutter my house for at least 3 years, but it's really hard to actually do it, especially when you have the space to store things. Now just extrapolate that up to a whole society, collectively going through the same process, but because they're all in a similar mindset, that just reinforces the idea that this is normal and the right thing to do.
It's weird though. Whenever I'm walking down the road, and someone has their curtains open and the lights on and you can't help but look - whenever I see something really sparse - a sofa, a TV, maybe a cabinet or bookcase, I feel so jealous that I can't just do that myself. It's not like I even need to buy anything to make that happen, I just need to dispose of everything else!
Personally, I've made a plan to take at least one full carload of stuff to the tip and take a bag of stuff to a charity stuff over this Christmas holiday, just to try to start the ball rolling on changing my mindset. But I know it won't be easy, because I've had the same thoughts in previous years...