An abandoned city being re-settled by a small group of determined homesteaders. A group of survivors left in the wake of a plague. A small religious cult isolated from the rest of society. There are any number of creative and interesting excuses to have a group of 15 or 20 folks gathered in some corner of the world just waiting for your dual glass dagger wielding elf to wander by. And, of course, there are examples to be found in Skyrim.
Of course, you couldn't tell the stories Skyrim aims to tell, complete with warring jarls and property-owning thanes, without rough approximations of towns and cities. I understand that and accept it as part of the language of TES. This isn't a criticism of the game that has eaten every second of my free time since 11-11-11. And I would certainly rather see the processing power devoted to other pieces of interesting content rather than town folk filler that are little more than props that grumble, "Sorry, too busy to talk. Gotta get this arrow out of my knee" as you walk by.
How 'bout you? In your next open-world RPG/adventure game, would you prefer conspicuously under-populated cities with furnished homes to rifle through, a smithy and a chemist, and a few citizens-in-need to send you on errands to retrieve lost heirlooms? Or would you be willing to forgo the great halls and majestic manors in favor of more modest settlements, camps, trading posts, drum circles, hunting parties, caravans, acting troupes, or outposts -- anything that you would actually expect to consist of only a couple dozen people?
My answer is, I'm not sure.