Don't live in LA but did in the past. I pretty much lived within 5 mile radius of my apartment, so biking is very doable. However, with the city sprawl I often found myself travelling 40 miles RT to see friends, go to an event, etc. As much as I am pro biking, I just don't think it is that practical for people in LA to completely give up their cars. It is entirely feasible for them to greatly reduce the reliance on their cars though.
The new bus lane network will have to be very extensive to be practical IMO. This is a lofty goal and one I would like to see completed.