Another reason why more plus size clothes don't exist?:
the comments are actually intelligent and thought-provoking.
I particularly love this comment by ceruleanshipper:
So among the fun things one can find on the Internet are CDC statistics on Americans’ height and weight. Interestingly enough, a set of data I found also includes data on American women’s waist sizes - in centimeters, but easy enough to convert in a spreadsheet. Warning, boring statistics ahead.
The average American woman’s waist is 37 inches around; the median is 36.2. So obviously the tail’s longer on the fatter end of the spectrum. This is borne out through looking at the 5th through 25th percentile measurements versus the 75th through 95th percentile measurements: the thinnest quartile of American women have waists ranging from below 28 to 32.2; the fattest quartile of American women have waists ranging from 41 to above 48.5. So plus-size women suffer from the “long tail” - e.g., women who wear a size 4 are more common than women who wear a size 24.
But. Using the JCPenney.com size charts, and considering a -4 inch effect through vanity sizing (seriously, does anyone wear the size the chart tells them? No. You wear two sizes smaller, as though you were a Briton shopping in America), this means that straight sizes top out at a (hypothetically 37 inch, really 41 inch) waist.
Which leaves out 25% of the populace. And this is a conservative estimate using liberal assumptions about vanity sizing and size charts from one of the most middle-American (read: liberally fitting) stores in America.
I believe the market can accommodate at least three or four middle-to-high quality clothing stores for the plus-size market, each one catering to slightly different body types. (E.g. J. Crew is not the place to go if you have narrow hips and large breasts.) FWIW, Talbots seems to do okay with its plus-size collection.