From the Associated Press article:

Neighborhoods and commercial areas with a mix of older, smaller buildings make for more vibrant, walkable communities with more businesses, nightlife and cultural outlets than massive newer buildings, according the National Trust for Historic Preservation’s study.
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“There is a lot of economic capability in older and smaller buildings and in historic districts that’s often overlooked,” she said.
The study is the start of a larger initiative also examining Baltimore, Philadelphia and other cities with less robust real estate markets. Researchers also want to know whether their findings hold up in younger and smaller cities as well or less prosperous areas.
“We hear from time to time, ‘well, it’s just easier to tear it down and to start over,'” Meeks said. “So we feel compelled to put the strongest argument forward that it’s worth the effort to invest in these places, not just from a cultural standpoint but from an economic standpoint.”