As always, the erroneous assumption of outside observers is that these backward people created their own nightmare.
At Home in the Heart of Appalachia, John O'Brien

Appalachia on the eve of industrialization was a land of scattered, loosely integrated, and self-sufficient island communities. Separated from each other by a sea of ridges, mountain communities had developed since their founding as separate social systems living largely unto themselves.   Miners, Millhands, and Mountaineers, Industrialization of the Appalachian South, 1880-1930, Ronald D Eller

Eller's description applies to Appalachian regions far from the Ohio River and the Great Wagon Road through the Shenandoah Valley. Pittsburgh and Wheeling were developed as centers of the   iron industry before the Civil War, and the prosperous farms and towns of the Valley were in constant communication with the eastern cities they helped feed. For communities deeper in the mountains, drives of cattle, pigs, and even turkeys to lowland markets did link many mountain farms with the world beyond, as did such events as the 1830s gold rush into   northern Georgia  and the development of copper mining in   Polk County, Tennessee, after 1843. However, it was not until after the Civil War that the highlands of Appalachia were incorporated into the new America of massive industrial systems and a culture increasingly devoted to the consumption of the products of industry.

When Frederick Law Olmsted traveled in 1854 through the "back country" back and forth along Tennessee's borders with Georgia, North Carolina, and Virginia, he found a people "open-hearted, frank, and kindly," but ill-informed about the world beyond their settlements, and living in a rude fashion, in "small and comfortless log huts," practicing a backward form of farming. ( Journey in the Back Country, 230-32) He reported that there was great expectation that life would improve with the advent of railroads:

The Baltimore and Ohio Railroad crossed western Maryland and Virginia to the Ohio River at Parkersburg by 1857; between 1854 and 1857 railroads built from Knoxville, Nashville, Memphis, and Atlanta connected in Chattanooga; and in 1858 a railroad connected Knoxville and Richmond via Bristol. The great expansion of railroads into the mountains began after the War. Authors such as Eller and Ronald Lewis (Transforming the Appalachian Countryside: Railroads, Deforestation, and Social Change in West Virginia, 1880-1920), tell a tale of rails snaking their way, decade after decade, into the mountains, bringing with them exploitative industries and new ways, ways not ultimately felicitous for either mountaineer or the highlands.

Courts shifted from a concern for the cows and horses being slaughtered by the new locomotives to an assumption that livestock should not impede transportation. County seats shifted from old agrarian centers to towns along the tracks. Over time, the appeal of industrial development dissolved old political divisions into a bipartisan welcome for the railroads and the new lumber and fuel-extracting industries. By the beginning of the 20th century, West Virginia politics were under the hegemony of the industrialist-senators, Republican Stephen B. Elkins and his father-in-law, Democrat Henry Gassaway Davis. As the 20th century progressed, large-scale enterprises begun by entrepreneurs living the mountain region tended to be bought out by corporations outside the region, joining the long list of industries begun by outside concerns.

Since the 1960s, many scholars have described Appalachian post-bellum history as that of the development of a resource "colony" of industrial concerns headquartered outside the region. In Appalachia's Path to Dependency, Rethinking a Region's Economic History 1730-1940, Paul Salstrom points to the post-bellum capitalist exploitation of the southern Appalachian mountains being aided by four factors:

A) The mountain population increased at a time marked by
B) increasing depletion of the arable land and
C) destruction of much of the region's infrastructure during the Civil War. After the War, federal legislation
D) opened prairie regions to homesteaders in competition with mountain farming and concentrated financial resources in major cities.

By the 1880s, family farms were divided into smaller units to allow sons to be owners, but often the land was wearing out, or agricultural production was being pushed into lower quality portions of the homestead. The often-republican mountain counties of ex-slave states were not being aided to any great degree by redeemer democrat state legislatures to rebuild after wartime destruction. Major competition in farm production was coming from the newly-homesteaded plains states. At the same time, new laws concentrated money and banking more than ever in metropolitan centers outside the southern Appalachians, crippling development of new economic initiatives by mountain entrepreneurs. Over time, the timber, oil, and coal industries would be run more and more by outside corporations.

The coming of industry to the hills did not mean that the older traditions of subsistence farming and barter exchange disappeared from mountain populations. Rather, a wage/store-bought-goods economy existed in many families along with the older lifeways. Many a family mixed old-style farming with some men-folk going into the mines or factories. In Salstrom's words,

The burgeoning capitalist relations were characterized by contracts (such as labor in exchange for cash wages, or for "in kind" wages, or for company-scrip wages) and by cash or scrip purchases of store goods. Meanwhile, the continuing, and indeed thriving, "traditional" relations remained based on networks of voluntary reciprocity, including labor exchange.  (127)

He sees the mixture of the old economic ways with the new kept wages low, allowing Appalachian products to undersell competitors. However, according to Salstrom, this dual economy set mountaineers up for dependence on federal support payments when the Depression came and Appalachian extractive industries ground to a halt. He writes, But why, if the subsistence-barter-and-borrow economy thrived during Appalachia's industrialization era, did so many of Appalachia's people eventually find themselves in need of federal relief when the industrial economy faltered? The answer is that, by continuing alongside outside-controlled industrialization, the continuing networks of mutual aid served to reduce wage demands and thus to transfer Appalachia's wealth (in the form of labor's products) outside the region. The long-term effect of continued low money networking among industrial workers was that the workers subsidized U.S. industry at their own eventual expense.  (127)

With the decline of Appalachian agriculture, the rationalization and mechanization of the coal industry after World War II, and the deindustrialization of America after the 1960s, millions of Appalachian folk left the mountains after 1940. In the coal counties of Central Appalachia, large percentages of the population remained un- or under-employed after 1950, even during the energy industry boom of the 1970s. The coming of industry to the mountains resulted in the coming of wealth to only a small percentage of the Appalachian folk.