The most obvious difference is cost. Some of the premium goes to pay for lavish or exotic materials. Gehry, for instance, used titanium at Bilbao. Sometimes new or experimental construction methods raise expenses. The budget tends to grow as the project proceeds, much more so than with conventional buildings.
Projects begin in one direction, then change course as details and desires become fact.
The university had the good fortune to have in Peter Lewis a donor devoted to Gehry. He upped his contribution as the costs rose, maintaining his commitment to fund 60 percent of the project. Indeed, the expense of a trophy building can sometimes be offset by its ability to excite high-end donors. To be fair, though, project costs don't always have to be astronomical. We don't want that to be pedestrian, and he supports that effort.