Is it "death of distance" or is it agglomeration? It is both. False choices mislead. We keep getting clusters of complementary activities but the new clusters are at lower densities and more spread out.
Today's WSJ includes "Startups Try to Spread Outside of Silicon Valley ... The biggest, best funded companies are still being built, for the most part, in the Bay Area." This is not surprising. All of finance was never expected to be in Manhattan; all or entertainment was never expected to in in "Hollywood"; all of the auto industry would not be in around Detroit. But these places maintain(ed) leadership. Clustering will always be attractive but clustering with elbow room is better.
Here is the map of the many shapes, sizes and densities of the many Bay Area clusters.