I think you missed a nuance...
Light is ever changing. So if you were to photograph something, you'd only capture that moment.
Because as the light changes, so would what is captured.
Thinking in the infinite...
I also do not believe anyone has photographed everything. So there is probably a lot of things never photographed.
People trample flowers to take a picture of the hill or field of flowers.
To add to this thought, every moment on this earth is unique. The light, wind temperature all change dynamically and continuously. So, unless there is a constant "video" or photo sequence of every landscape and macro scene in creation. Ans as far as subjects go, yes many have been photographed, but surely nowhere nearly as many by YOU with your eye/composition/ lighting and choices of focal length, exposure, white Balance and cropping and PP with your favorite techniques and tools.
One of my favorite books is John Sexton's of Ansel Adams's photos re-shot from the exact locations. And sure 'nuff, they look WAY different! Because of the materials. equipment, color and, of course, the "artful dodger's POST processing. ANd I'm sure if that was re-visited with today's modern Digital Tools, these same already photographed scenes would look, quite again, WAY different.
So, while it's an interesting thought, the better question from MY point of view is "what hasn't been photographed by ME---LATELY." That's a creative way to look at it.
And as far as people, there isn't a burst mode fast enough to keep up with the many changes in position, breathing, eye movement, expression of even tho most sedentary model. So, keep sitng the difference, newness and nuances that make our art form challenging and satisfying. This is what making pictures vs. capturing pictures is all about.
http://www.nps.gov/deva/photosmultimedia/images/Photographer-in-flowers.gifhttp://www.nps.gov/deva/photosmultimedia/index.htmI think you missed a nuance... br Light is ever ch... (