I only buy what I need when I need it. Furniture that is well made will last for decades; there's no need to replace it every couple of years. The only exception might be a bed since a mattress is something you are supposed to replace every eight years. If people are selling the old stuff or giving it away, that's fine, as long as they can afford the new things. I prefer to use my money for things I actually need.
If it were part of their culture, then I don't think we can say anything about it. If they are able to afford it and it is who they are, then leave them that way. After all, you have your own culture. And in terms of other countries, of course there are a lot who don't have people regularly changing their furniture for possible reason that it's not with their culture and that they find it unpractical.
I think it's a part of their culture yes, but at the same time it's a society where they have way higher incomes than we do, so it's a rich culture because if I had a lot of money I could spare in furniture I don't need maybe I would... buy a great vacation for me and the family in a tropical country? LOL, I don't know, it just seems strange to me buying new furniture when the furniture you have is still good.
I think it's a waste of money to change your furniture every couple of years unless it is damaged. There are so many better ways to spend money, like paying off debt or buying a car, so why would someone get rid of useful furniture every couple of years?
I'll tell you why, but you know it too, the people that does it has no debts and earn more money that they can spend, so they literally don't know what to do with the money and they spend it in superfluous stuff. I would never do that, if something is good I am not trading it, I see no point in that.
Over here in our home, the furniture only gets replaced when it looks worn out already or when they feel like changing it even if it still looks decent and presentable. The old furniture just gets dumped in the backyard, they don't give it away. I also seldom notice furniture waiting to be picked up by strangers. I guess only rich people do that, and I don't live in an exclusive area.
Unfortunately my brother just got a divorce and he temporarily returned to my parents place. He brought some furniture with him and he got rid of the one that was in his former bedroom. He placed it in the street and guess what, less than one hour after that old furniture was gone, someone took it, lucky them!