Making a walkable LA would mean making a much smaller urban area (or series of much smaller) with much higher population density and ideally rewilding most of the LA metro area. It is functionally impossible in the current political environment.
It's stupid that I even have to point out a few things. Like that I was born in Europe, have been to Germany and Japan, and lived near NYC for a time so I probably know better than some European about my own city.
At least my definition of walkable does not mean "you can technically walk there" it means "if you live here you will not want nor need to use your car"
Santa Monica and downtown are now directly linked with the yellow line.
But LA has a great many neighborhoods that are very walkable, and it has public transportation connecting all those walkable neighborhoods.
And in response to your spurious claims about Santa Monica: the entirety of the city of Santa Monica is just as walkable as the cities of London and Paris, and definitely more walkable than the outlying neighborhoods like Versailles.
Downtown Los Angeles is also very walkable, and there are tourists who make that walk every day.
In the same way that Everest is walkable. None are walkable cities by any reasonable definition.