Some great conversations in here. As ravenshrike pointed out, Pandora's box has already been opened, and the idea of pulling off a transportation about-face seems far fetched. But as I see it, the only way to undo decades of short-sighted greed, based policy is to stop blindly supporting the current infrastructure simply because it is the only one we know. Seeing the problem as inevitable is part of the problem. LA is in a pretty deep hole, but reintroducing more electric options to the daily commute would be a big step in the right direction.
Fortunately, light rail is starting to make a serious impact in certain mid-sized cities across the country. Many cities in Europe and Asia are a few decades ahead of us in that respect, but better late than never.
Trams are outdated, by this point there is no sense in creating shared road space with vehicles, because trams are subject to the same laws of traffic as private vehicles, while trying to maintain a consistent schedule. Dedicated light rail systems (on the ground, underneath and/or elevated) are the best way to present a network of travel that doesn't interfere with the preexisting road infrastructure, but rather offers a reliable alternative for the daily commute of many. This infrastructure already exists in the biggest cities in America, but there are so many communities either just starting out with light rail, or just depending entirely on their freeways for lack of any other option.
Youtube has a great documentary about the LA situation called "Taken for a Ride [https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwip-66I9cXKAhUBOyYKHXLJD94QyCkIHjAA&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dzy37YoQ2CJw&usg=AFQjCNHRPuOdP4Cv4bozUSdqWAhR6xm9jg&sig2=ZLMHwqs4D0oBAHrjztFA6g&bvm=bv.112454388,d.eWE]" It's about 30 years old, but well made, in my opinon.