After the Civil War, Americans were obsessed with science and technology – bringing the sewing machine to common use and new synthetic dyes along with exponentially increased improvements in the textile and garment production industries. World wide trade and the full access to the Asias had the Middle Victorian Era full of new ideas that could be gotten for cheap.
The crinoline evolved into the first bustle era, the smaller ones like tournures and wire and tape bustles or padded rumps from about 1873-1877 (during America’s reconstruction where there was a “high low” class disparity in the “Gilded Age”) when suddenly all understructures disappeared during the “Natural Form Era” for about 3 years.
Garment construction changed to the long lines and lean fronts of the Princess and Cuirasse silhouettes. Much of that was due to easier and cheaper access to fabrics and trims, plus the home sewing machine.
(Sketch: The Gilded Age made life very comfortable and fashionable for some, while not for others as this mid-1870’s drawing shows)