While A-pillars are indeed too wide and can create a dangerous situation, in my experience the main problem in LA, at least, is that too many drivers have a habit of looking in the direction opposite to the turn while making a turn. Even if there had been a seamless glass bubble cabin, humans don't have wide enough field of view to see anything over their shoulder while looking over the opposite shoulder. I used to walk to work in LA and was amazed how many people do this. Could be the same in other cities but I've not been walking much elsewhere.