Why is there an ancient "river to nowhere" in southern Ohio?

Southern Ohio, northern Kentucky, and western West Virginia are a unique corner of Appalachia. While the modern Ohio River is a key part of this region's identity, two huge, ancient river valleys that appear to lead nowhere still scar the southern Ohio landscape, with similar valleys visible in West Virginia. While they don't make much sense at first glance, these valleys have been extensively studied and paint an interesting picture of topographic change resulting from Ice Age climate. This video talks about the formation of the valleys and how events that "deactivated" there forming rivers shaped today's iconic Appalachian "holler" topography.