The Sochi Olympics end on Sunday. Another Olympic torch extinguished. Another bank vault full of gold medals awarded. On to the next town—Rio de Janeiro in 2016.

Though it may be too early to sum up the Sochi effect, other than hotels-built-while-you-wait, "bars that look like dentists' offices" (in the words of a New York Times reporter), and tweeted photos of communal toilets, a postmortem of the 2012 Summer Games held in London and earlier venues can be done.

Olympi-philes may remember that when London squared off against Paris to vie for the right to host the 2012 Summer Games, the deal clincher was this: London would not merely celebrate sport. It would use the games to jump-start