I live in SoCal, and I can't get my head around the car culture mentality. Of all the places that should be walkable, one that is 80 degrees and sunny 90% of the entire year should rank very high on the list. But nooo.... the walkable cities are in places that get run over by a glacier every six months. Go figure.
I'm all for public transportation and LA used to have the best in the world 80 years ago. But, a large city as large as LA is never really going to be completely walkable unless everyone always moves close to their job. That would mean moving away from friends and family because of a job change rather than just commuting a little further. I suspect most people would chose to stay near their friends and family rather than move closer to their job.
You can compare Tokyo which is large like LA but which has excellent mass transit and yet the average commute is 80 minutes each way. Why? People can't or won't uproot their families for new jobs. Also housing close to a job is probably also often either too expensive (downtown) or undesirable (industrial area).
In the valleys, walkability runs into the heat problems in the summer. Walking in 100F+ is no fun and can be dangerous to some.
There definitely is a very strong desire still for wider spaces, bigger yards, etc. As the result, walking in most of inland sprawl take a lot more time and effort.
Big cities on the east coast are older, so didn't develop in the age of the automobile and have to conform to its needs. Except cities in the SE, which again, grew due to modern appliances like the air conditioner.
This implies that walking has a hard limit on desirability, which is easily topped by driving, even with the worst traffic. You have to make driving worse to tip the preference toward walking, even if the conditions simultaneously make walking less desirable.
If driving 5 miles is likely to put your car in a ditch, you may opt for a 200m walk, which may only plant your ass on the concrete once or twice. If you have to shovel snow for 20 minutes to drive anywhere at all, you may prefer to just pull on some wellies and hoof it through the drifts. If every mile you drive is rusting away your vehicle's underbody due to road salt, you may prefer to wear away your boot soles instead.
If you could wave a magic wand to install a roof over ever road and highway, the residents would squeal with glee, toss out their tire chains, shovels, and boots, and get right back into their cars.
That's Stockholm Syndrome, is what that is.
Except freezing rain. That stuff is the worst.
 - https://en.wikipedia.org/wiki/Pacific_Electric
 - https://upload.wikimedia.org/wikipedia/commons/2/2e/Los_Ange...