The Sword Coast is more settled than the zoomed-out maps make it look. There are lots of little farms, villages, thorps, hamlets, communes, and the like that simply don't get included on the maps. The area between Waterdeep and Daggerford is basically all settled farmland. Most of the area between Waterdeep and Red Larch is the same. There may not be a Kingdom of Waterdeep governing the region, but it is nowhere near as empty or uncivilized as it looks on the map.
That being said, I'm not really talking about the physical aspects of a PoL setting but more the metaphysical ones - technology, attitudes, politics, etc. It's been a long time since FR societies were small, isolated communities with little outside contact. Even with the vast distances between them, there's a lot of trade and communication going on. Groups like the Lords' Alliance provide military and diplomatic alliances.
Then you've got stuff like Baldur's Gate with its steam-powered cranes in its port, and Waterdeep appearing more like its in the 1700s or 1800s in much of the Dragon Heist art.