a 100 years ago, there was racing in California streets with stock cars. Why can't we do that anymore?

There was racing in Venice California

http://autoweek.com/article/car-life/when-men-were-men-venice-grand-prix-turns-100

there was racing in San Diego (Eddie Rickenbacker)

there was racing in San Francisco! (Again, Eddie Rickenbacker, same car, both photos from http://commons.wikimedia.org/wiki/File:Eddie_Rickenbacker_-_Maxwell)

From the first course around the Coliseum in 1903 to the present day there have been 174 race tracks in SoCal. “More than anywhere else in the world,”

I'm not talking about million dollar race cars, I'm talking about your 24 thousand dollar daily driver commuter from a dealership. In city streets, you aren't going to get going much faster than 100mph, so you won't need racing tires, or racing engines, or racing cars... just a new car with airbags, air conditioning, and the time to have fun!