Francesca Mari traces the history of the word:
[H]omesickness didn’t come into use until the 1750s. Before that, the feeling was known as "nostalgia," a medical condition. … By two years in [to the Civil War], two thousand soldiers had been diagnosed with nostalgia, and in the year 1865, twenty-four white Union soldiers and sixteen black ones died from it.
Meantime one hundred thousand Confederates deserted, presumably motivated by memories of mom’s hushpuppies. The war just about ended what little romanticization of homesickness had survived in the wilds of early America.
Libby Copeland applies homesickness to today's culture:
[Author Susan J. Matt] wonders if, in the face of rapid change, we have sublimated our longing for home, for the way things used to be, into a passion for retro objects. This type of nostalgia lets us signal cultural hipness instead of the rootlessness and neediness we feel deep down.