Don't get me wrong, I love Fallout 4. I just find the 200 years have passed thing so inconsistent with the evidence that the world offers.
Let's look at history for just a moment to get an idea of just how long 200 years is... That would be around the year 1815...
The French have one of the strongest militaries in the world. THE FRENCH!! Napoleon is leading a conquest expedition eastward into the Netherlands.
Slavery has not yet been abolished in the United States because the Civil War has not yet been fought.
In fact, the United States is just now finishing a second war with Britain. Britain has invaded the United States and has burned the US capitol. And the United State's invasion of British held Canada is thwarted by Native Americans... (yes this happened).
The Star Spangled Banner is written in 1814, inspired by the Battle of Plattsburg as the United States repels the British attempt to invade New York.
Napoleon is defeated in Waterloo and the United States and Britain make peace so that Britain can focus once again on the French as they begin to withdrawn their resources from Napoleon's campaign and once again become a threat to British soil.
That was the United States 200 years ago...
That's how long 200 years is in terms of human history.
If we decorate for halloween and then the world ends... there aren't going to be little pumpkin buckets and pumpkin decorations lying around 200 years later.
Very few of the original buildings are still going to be there 200 years later... there might be some pieces of old building patchworked together or refurbished with replaced lumber.
But after 200 years... if it wasn't made from stone and mortar or concrete, it isn't going to be there any more... and unless it got upkeep, it isn't going to have a roof anymore.
And considering that each generation is seperated by 20-30 years... we are talking 7 or 8 generations of people passing through in 200 years...
How many resources left over from 200 years ago do you image are going to be left 7 or 8 generations of scavengers later? None
There aren't going to be above ground buildings that have gone unexplored and unsquatted for any amount of time.
200 years later, you aren't going to be scavending whole desk fans... at that point you'd be happy to find a few uncorroded bits of scrap metal that several scavenges ago used to be a desk fan...
And imagine trying to eat or drink something the pre-dates the civil war... you might as well just try to eat dirt because a 200 year old soft drink or box of cereal is going to be dirt.
Again, don't get me wrong, I love Fallout... but this is just a part of the universe that I find... un-immersive...