Because the very same Santa Monican NIMBYs that just passed that law have made it impossible to build more housing: http://www.santamonicanext.org/2015/05/santa-monica-city-cou...

As an aside, if anyone is looking to locate a startup in Los Angeles, do your future employees a favor and avoid Santa Monica. Downtown LA and Culver City are far more sensible options and allow for a reasonable commute and/or nearby housing at lower prices than Santa Monica.

Phase 2 of Expo line is scheduled to open early next year http://www.metro.net/projects/expo-santa-monica/