I don't really agree. If you'd look at some comparison pictures you can find on the web, you'd see that many Washington locations are actually a rather faithful and accurate rendition (though the scale and distance between those areas are obviously reduced by necessity) of the real thing.
I know nothing of the actual locations, so I'm just going to nitpick based on the photographs provided.
*NITPICK MODE ENGAGE*
First of all, we can see a very obvious architectural difference in the stairs leading up to the memorial. The F3 version terminates the stairs at the wall, which is also far more pronounced than the one visible in the RL version.
In addition, the F3 screenshot uses a uniform density for the pillars, the RL version appears to use a larger diameter at the base and shrink slightly as it reaches the top.
Lastly, the appearance of the walls are very different, F3 is a dull gray (with the green tint) and the RL version has many varieties of greys and other patterns which are completely absent, implying they're made from completely different materials.
The stairs have horrible shading, but the only thing I have to nitpick here is the fact that the apocalypse and 200 years of exposure to the elements only served to dirty the banners and render them incapable of reflecting light. As opposed to completely and utterly ruining them.
The RL version features wider top and bottom basins, and also much smaller ducts.
The F3 version also appears to consist of several different materials, which is the only explanation I can fathom for the parts discolouring differently over the course of 200 years.
On the subject of 200 years of rot, the fountain is completely unmaintained and should have fallen into a state of disrepair in that time. Also considering that it never rains in this shit-hole, the fountain should be completely and utterly dried up.
Then there's the stuff Azreal The Cat mentioned about the statues being the entirely wrong gender, among other things.
*NITPICK MODE DISENGAGED*
Of course that's not everything the term 'world-building' should entail
Agreed, when I cite world building, I explicitly refer to those other things, not being an American I really couldn't give a fuck about how well their monuments were recreated in a video game.
They're okay at the superficial stuff, but when it comes to any detail work, the only thing that comes out of them is sheer ineptitude.
They abuse the same small collection of tile sets (Ruined Interior, Utility Tunnels, Metro Tunnels, Factory, Caverns) for nearly all the areas, meaning that everything looks the same.
They are not good at area/level design, so areas not only look and feel the same, they are often practically navigated in the same way too.
There's almost no variety, and far too few exceptions to the above points.
They can't even manage something as simple as making the interior of a town hall look like an actual town hall,
And that's before we even jump on the myriad of issues with the setting their incompetent "world building" introduces.
Like the fact that there's no agriculture after 200 years, that nothing is growing, that no one produces anything, etc.
Basically everything sea and VD have stated on numerous occasions.