We can suggest that isn't the reasonable question, going to extremes here, by the observation that we don't just connect all our houses by interlinking corridors to create the "biggest houses" possible (well, ok, some particularly ostentatious americans do pretty much that with mega-mansions, but I would argue that's pretty much obviously conspicuous consumption which is itself an interesting phenomenon).
Put another way, in addition to the obvious considerations: cost, depreciation, heating, etc, shelter and design also provide the ability to bring things together into proximity, emphasise, demarcate and exclude.
Design in houses is the same as in all things: the biggest car is not the best, the biggest desk is not the best, the biggest bookshelf is not the best, the biggest kitchen is not the best.
Or like in computer design, packing things too tightly together is bad, but spacing them too far apart is as well.
Perhaps there is a particular note that American culture has tended off to right of the bell curve in many things on the size scale: biggest food servings, bigger cars, big houses, etc. As the article notes, wealth clearly has SOMETHING to do with it, but there's also clearly something else going on, because people with a lot of money and from other cultures are fully capable of looking at some of those things and judging them as poor/bad.