Man this is America. If people had any interest in walking, our national health picture would look very different. Even huge swathes of people voting for public transit in the US are doing so because they want everyone ELSE off the highway.
There's definitely amenities that can be done to make LA walkable regardless, but I understand that nature did not intent for this settlement to be human friendly.
It wouldn't, you'd need to change the food industry for that to happen.