Virginia had a lot of land and it was a slave-holding state. But the western part was in the mountains, where it wasn't really feasible to have a plantation or conduct large scale trade. Waterways were the most efficient way to trade. By the time the Civil War rolled around, Virginia wanted to continue slavery, but the people in the mountains didn't really give a fuck. They were poor and didn't want to fight for the plantation owners.
Post war, WV continued their status quo as a poor mountain state with mineral resources but not much else. Virginia continued to flourish with its arable land, cities, military facilities, and ports.