Yes, L.A. is spending enough on earthquake precautions. The 5.1 earthquake that recently hit the L.A. area is a reminder that California is earthquake country. Anyone who lives in California knows that earthquakes are possible at any time and they should be prepared. If people are not prepared for earthquakes in California, it is doubtful that more spending on earthquake precautions would change anything.
LA as well as other cities do a lot for earthquake prevention including different building regulations that help lessen the impact of earthquakes. However there is nothing you an really do when it comes to a massive earthquakes. You can never be too prepared for disaster, but they do enough.
No, hypothetically you can never spend enough. You can not ever put a price on saved lives. Realistically though the government will only spend a certain amount of money. It is good that they are trying to retrofit certain buildings to make them more safe during earthquakes though. It's at least a step in the right direction.
I am not sure about the effectiveness of all the measures that L.A's government has implemented in the last three decades to prevent a disaster caused by one of these earthquakes. I think that people have the right to be informed about how serious this situation can become, and its possible risks,