It's not that 40k is poverty. It's that 200k doesn't buy what it used to, and it's not enough to make you not worry about money.
I'll give you an example and put myself out there. My wife and I make between $150k and $200k a year. We do live in a very nice house (3000 square feet plus another 1500 square feet in the finished basement with a theater room.) We drive nice cars - both of us now drive Acura TL's. We save a reasonable amount (a little more than the 6 percent that our company matches) and we travel a least once a year to Brazil to see my wife's family.
But we also both work, our daughter goes to public school for kindergarten and a very much middle-class day care after school. We eat out maybe three times a week, and it's not unusual for us to eat fast food (less so now since I started losing weight). I cut my own grass, and while we have someone to help clean the house a few days a week, my wife still cooks most meals on the weekends and washes clothes.
So I wouldn't call us upper class by any stretch. I appreciate the good life we have, but we both have to work for it, and it's not like we go to the country club and sip mint juleps all day. My life sounds to me like it's solidly in the middle class, albeit maybe a little more money than most.