With the beginning of the 20th century, and the subsequent beginning of the relaxation of social rules that came along with WWI, the creation and use of parures of gems faded out altogether. Such formality didn't fit the race to modernity that we embarked on. All that remains is the matching set of earrings and necklace, which exists at every price level.
Now in the 21st century we seem far more interested in not matching things than we are in doing the perfect coordination thing. I suspect that has a lot to do with the vast increase in our access to the world's different cultures, and all they produce.
Who knows where we will decide to go next? Perhaps one day we will need the reassurance of a perfectly matched set of jewels to make us feel secure again.