Probably not the thread for this, but the empty storefronts are the fault of the Westwood Special Plan Zoning. They make it near impossible for any "college town" type of establishments like bars or quick-service restaurants to move into empty spaces. They only want retail, and with no parking and competition from 3rd Street Promenade and Century City, there's no way a high-end retail will open there. So the places stay empty.
Just as an example, I wanted to open my Poutinerie close to UCLA and I was told I could only take over an existing QSR. Not even a regular restaurant. So when Fab's closed, I tried to get that spot, but the competition from Pieology and I'm sure lots of other places made it impossible. Just around the corner are some great spaces, but they're not QSRs so I can't convert them.
Anyway, rant over.