Among the Chicago properties that needed to be reinvented, she cited the Brickyard Mall, recently redeveloped from an enclosed mall into a lifestyle center. "The old concept didn't work any more, so it was reborn as an open-air, easier access center," she said.

Holland, who is head of a family business that has owned malls for decades, said—in a variation of a long-standing idea in real estate—that "location drives whether a center can be redeveloped or de-malled. The market is going to tell you what's going to work."

But she added that change is inevitable, and necessary, even in well-establish malls, such as Abbell's Merle Hay Mall in Des Moines. "In the first 40 years after it was built, the mall had only one change in anchor tenants. Since 1999, there have been two, and we don't know how the Federated-May deal is going to affect the property yet."

Recently, Target agreed to move into Merle Hay. At first, Holland related, she wasn't sure how the existing tenants would react, especially Sears. "It turned out that all the other retailers were glad that Target was coming in, and we were able to attract other retailers as well because of Target, such as Starbucks. Starbucks has been in Iowa only two years, so that was a big deal."

Hardwick brought an historical perspective to the discussion, Recently he authored a book called Mall Maker, a biography of Victor Gruen, an early mall designer. "The idea of the shopping mall was actually a planning idea as much as a retail idea," he said, noting that it had emerged in the 1920s among planners as a way to concentrate retail and prevent sprawl (the audience laughed at that).

"Public housing advocates pushed the idea of the mall as part of mixed-use developments for the middle class," he noted. The idea didn't really take off until World War II, however, when the U.S. government hired designers to build entire cities for war production, part of which included the proto-mall concentrations of retail.

As a commercial venture, malls didn't really take off until the 1950s, with such pioneering ventures as Southdale in Minneapolis, and early suburban Chicago malls like Old Orchard Shopping Center in Skokie, IL and the Oakbrook Shopping Center in Oak Brook, IL. "Malls were conceived as multi-use," he said. "Sometimes the older malls had features you wouldn't expect, like public artwork, landscaping and detailed architecture." In at least one case that he knew of, one mall—Randhurst in the northwest Chicago suburbs—had bomb shelters when it was new.