] I'm curious...gigot sleeves and similarly poofy 19th century fashions required plenty of material, as opposed to the simpler 1800-1820s styles. Can we take this as an indication that as the 19th century progressed, more people were becoming wealthier, and accumulating more disposable income to be spent on fabric? And that fashion reflected this change?

] Just an example: in the 1940s, women's fashions were very slender and tailored as part of the push to economize for the war effort (there was even a U.S. government office in charge of dress patterns). A few years after the war was over and manufacturing of domestic goods kicked in - POOF! Out went the form-fitting look, in came yards of skirt.

Hmmm, interesting, but I don't think this idea holds up to examination. If women's fashions are narrow in "tight" times, why did clothes shrink down to a never-before-seen minimum in the boom 1920s? Skirts dropped lower again, and then shoulders gradually broadened throughout the depressed 1930s. Also, it's true that in WWII clothes and fabric were rationed, and people were forced to stick with trim lines, but Dior came out with his "New Look" (tiny waist, huge full skirt) while rationing was still on. It took some hideous number of coupons to buy a New Look suit, but everybody was starved for new style and jumped on it anyway.

If anything, I think lean times are likely to make conspicuous consumption all the more glamorous, whereas in plush times you stand out more by being stylishly spartan. Look at the way thinness has become more and more desireable as food has become more plentiful.

Also, Regency styles varied quite a bit between 1800 and 1825, and some of those styles require a lot more fabric than others. The round gowns of circa 1800 were actually quite full - the ladies in fashion plates of that period look rather like sofa bolsters - and usually trained. Ladies' clothes reached their slimmest (and least yardage) around 1810, and then skirts started to be cut with wasteful gores and decorated with flounces. The styles of the early 1820s, while still relatively slim in sillhouette, actually often hide quite a load of hidden yardage in their self-fabric decorations - pleats, puffs, flounces, ruffles, and especially all those bias-cut strips for the piping trim, as shown at the top of the page trimming almost every seam edge plus used as applied decoration.

And imagine the fabric required in all these little puffs (this is a ballgown of 1825):

On the whole, going from narrow to full sillhouettes just seems to be one of those things that fashion regularly does in order to remain fresh. Moderately poofy in the 1790s, tall and narrow in the 1810s, hourglass and highly decorated in the 1820s, very broad and poofy in the 1830s, slim on top and broad on bottom in the 1850s, slim though bustled and highly decorated in the 1870s, hourglass but elongated in the 1890s...I don't think it's possible to consider the 19th century as a gradual procession toward greater use of fabric.