A coalition of city officials and building-preservationists has begun trying to do something about it. The City Council recently approved a new adaptive re-use ordinance that should make it easier for developers to convert the CBD's stock of old industrial and commercial buildings into housing. And now, a new survey by the nonprofit Los Angeles Conservancy estimates that nearly 50 of Downtown's older commercial structures are ripe for conversion to apartments—a report that might kindle the interest of builders and real estate investors.

"Converting those buildings would be a great way to revitalize the CBD and, at the same time, save some very beautiful structures that are important parts of our city's history and architectural legacy," Conservancy Executive Director Linda Dishman tells GlobeSt.com.

It would also be an important step toward creating the type of 24-hour-a-day environment in Downtown LA that San Francisco, New York and some other big cities already enjoy. "To have a vibrant Downtown, you need people who actually live Downtown," Dishman says. "And right now, there just isn't a lot of good housing stock in our CBD."