The people portrayed here are on the extreme end of greed & materialism.
I once worked with an almost-billionaire family. If you ran into them in a restaurant, you would never know. They were out of the mold of Sam Walton. Ok, they drove Cadillacs, but Cadillacs with well over 100,000 miles on them. The rest of their vehicles were Chevy Tahoes or Ford pickups.
Further, there are tons of millionaires who saved their money over their life. They don't act like this, and they probably live right near you, but you wouldn't notice because they don't go overboard on their materialism.
On the poorer end of the spectrum, there are tons of "credit-card millionaires" - as I call people who make $100-300,000 per year but have no real savings and spend all their money on "glamorous" crap that fills up their homes. To me, the article is about people just like this, but who have secured more money - their behavior is identical.