Big ideas and small ideas

A recent article about Macolm Gladwell's new book in The Guardian draws attention, among other things, to his ability to articulate big ideas: the tipping point, outliers, etc. A recent profile of Larry Summers in The New Yorker notes that Summers' influence in the field of economics has been profound but he is known for many small insights rather than for one revolutionary big idea.

These observations raise the question of what is it that makes us long for big ideas? What form of messianism or salvation does the big idea promise?

And ten, twenty, fifty years from now, how many of these big ideas will endure?