Question is, will they try it? I think the failing if there is any failing, is that what value is there in being a hero or whatever, if there are few people in the world to theoretically take notice. It is simply to much isolation where there shouldn't be. I'm not saying it should be populated like an assassin's creed city, it would drive me nuts to get across town. Even if there were fake doors and non interactive NPCs it would make it somewhat more immersive.
That's the problem though- read your own post- "fake doors" would drive TES fans UP THE WALLS. They would literally go insane. Read the posts complaining about the handcrafted dungeons- Skyrim has some of the most beautiful, unique dungeons I've ever seen and people are complaining because "the loot is all the same" or "they're too small and there aren't enough passageways". Seriously, there's been dozens of threads.
There is NO WAY, ABSOLUTELY NO WAY Bethesda could EVER make a 'massive' city without cutting corners by populating it with NPC's that don't interact, houses that have no loot, etc etc. And people would lose their minds- "Beth makes the most boring houses ever!!!111 Every house just has chairs and apples and crap!!! The same books are in EVERY HOUSE!!! Bethesda doesn't make role playing games anymoarrr!!111"
You see what I mean?
They are in a no win situation.