A good friend of mine (who recently moved to DC) and I had long been fans of the "idea" of living in a downtown loft, and so, as some of the first lofts were going into downtown ~ 7-8 years ago, we went on tours of the buildings.
Many of the places were great -- but we both felt the prices didn't figure into it the cost of making that leap of faith moving downtown would entail. The developers were claiming back then that big retail establishments were just on the verge of committing to downtown -- and here, so many years later, few have (and almost none in the way of a Trader Joe's or B&N).
Also, a big part of the appeal of downtown living -- walking a downtown area, hanging out with friends, enjoying a vibrant cultural scene -- were not only lacking but probably not a good idea (at least the walking around after dark part).
I'm in my mid-30's now, and walking around downtown Culver City is plenty exciting enough for me. If downtown L.A. wants to become a magnet for nightlife and culture, it needs to do everything it can to get those things up and running before selling wary Angelenos on the idea of living there -- not the other way around.