A few details leave them worse off, as far as I can tell.
First, the items Chassidim use as signals are almost all consumable or have their costs over the long term, in contrast to the middle class. Weddings and kosher food are examples of the first type, number of children and isolation from secular knowledge/intensive religious schooling for young men are of the second. The middle class has expensive weddings and vacations, but primarily is enslaved to owned cars/houses or educations that merely fail to be fully worth their opportunity cost.
Second, having religious values in addition to other values deemphasizes the focus one can put on the other values. E.g., if I value my happiness, family, career, etc., I will put effort into each of them. If in addition I value baseball cards, I do so by taking money and attention from the other categories. It is true that one who only values happiness is unlikely to achieve it, and that valuing additional things such as the Yankees' winning would or does make some people happier. Nonetheless, the body of ordinances, injunctions, and so forth that these people are expected to follow is amazingly comprehensive and capable of crowding out much having to do with happiness.
The middle class has expensive weddings and vacations, but primarily is enslaved to owned cars/houses or educations that merely fail to be fully worth their opportunity cost.
I see quite a bit more stuff among the regular middle classes that looks like pure signaling waste, though you're clearly more knowledgeable how this compares with the analogous phenomena among orthodox Jews.
However, one very important issue you're not taking into account is that the primary objective that drives the North American middle classes to work their asses off is the need...
I was browsing my RSS feed, as one does, and came across a New York Times article, "A Village With the Numbers, Not the Image, of the Poorest Place", about the Satmar Hasidic Jews of Kiryas Joel (NY).
Their interest lies in their extraordinarily high birthrate & population growth, and their poverty - which are connected. From the article:
From Wikipedia:
Robin Hanson has argued that uploaded/emulated minds will establish a new Malthusian/Darwinian equilibrium in "IF UPLOADS COME FIRST: The crack of a future dawn" - an equilibrium in comparison to which our own economy will look like a delusive dreamtime of impossibly unfit and libertine behavior. The demographic transition will not last forever. But despite our own distaste for countless lives living at near-subsistence rather than our own extreme per-capita wealth (see the Repugnant Conclusion), those many lives will be happy ones (even amidst disaster).
So. Are the inhabitants of Kiryas Joel unhappy?