[T]hese differences are not simply differences in standards of living, important as such differences are.
This is indeed a somewhat complicated, but very common and very idiomatic, way of saying these two things:
- The differences in standards of living are important.
- However, the differences in standards of living are not the only differences that are important, and are not the most important differences. There are other, more important differences.
What you have here is a shorthand for both admitting that something is a) important but at the same time b) not important as something else. That something else being what the author is about to talk about or explain in greater detail.
So, let's recap the passage as a whole:
Geography is just one of the influences behind vast economic differences among peoples and places. Moreover, these differences are not simply differences in standards of living, important as such differences are.
Geography is responsible for vast economic differences among peoples and places. However, geography is not the only thing responsible for these differences. Additionally, while the differences we are talking about include differences in standards of living (and these are important differences), they also include other differences, that are even more important.
If you're still having trouble with this construction, we can simplify it even further.
Most simply put, "[as] <adjective> as X is" means "even though X is <adjective>" or "X is <adjective>, but".
There are many ways and opportunities to use this construction. As I mentioned before, it is used quite often indeed. Here are just a few examples from the Corpus of Contemporary American English:
It was easy for these subjects, important as they were, to disappear into abstraction.
→ These subjects were important. But they did disappear.
→ These subjects easily disappeared even though they were important.
In the heart of Seattle's busy waterfront I easily spied the gleaming white Yorktown Clipper, tiny as it might be compared with the giants.
→ The Clipper was tiny. But I was still able to see it.
→ I saw the Clipper, even though it was tiny.
Or will the Tesla, impressive as it is, be remembered as just another electric-vehicle science-fair project?
→ Tesla is impressive now. But in the long run it might vanish as a side note on the margins of history.
→ Tesla could be meaningless in the end, even though it is meaningful today.
And returning one last time to your original example,