It's easy to be fooled by the Golden Triangle. Most Pittsburghers have been for 50 years. We've looked with great pride at Point State Park and Gateway Center, the tidy clump of corporate office buildings next to it. And without thinking too hard about why their never-changing open spaces are so empty of humans so much of the time, we naturally assume they are an example of successful urban planning. But they're not, as New York Times columnist John Tierney, a former Pittsburgher, so cruelly but accurately pointed out in a recent op-ed piece that embarrassed Pittsburgh by exposing it...