If I'm reading your comment right, I think you agree with the actual policy proposal presented. LA currently makes it illegal to build density via mandating parking everywhere. Removing that mandate doesn't remove any parking immediately - it only makes future development able to increase the density over what already exists.

Also, the fundamental way to have density and speed is Transit-Oriented Development. Basically super-high density within walking distance of stations. That way the experience of walking to a station, taking the train, and walking to a destination near the end station is really good. The places between the stations can be lower density without really changing anything.