I don't get this discussion at all.
I am middle class by choice. I have wealth that puts me in the top 5% of the U.S., but live way below my means, and wouldn't have it any other way. I could retire today easily but won't (age 59). I drive a modest car and live in a modest home (though admittedly in an expensive city, which i love). I pinch pennies like the next guy and don't waste. I do all those things like getting cash back on my credit card, shop at Costco sometimes, etc.
Why? Why not buy up and spend it?
I'll tell you and this is the honest answer. There is so freakin' much poverty and wanting these days, from the family living in a van at the end of the street to the whole third world countries full of the destitute. I have everything I need and more. Why should I waste any of it on things I don't really need?
Yes, I am middle class by choice. And I question why someone would waste money on expensive cars, homes, etc. In my opinion, for whatever reason, some of us got it good - at least have enough decorum to not flaunt it when so many others are in need.
FWIW, I found it necessary to say this because the original poster was out of line in saying the markers of the middle class are "sad": "3 sad signs that you are middle class and always will be".
I could say a little more about what i think drives people in their pursuit of money, but save that for another time. It's not what drives some of us, and let's leave it at that.