In this case, some of these people have little choice. Rental spaces are far and few between and getting harder to find, and more expensive. I don't look at this as an expense. Rentals are an expense. You get nothing back after years of renting. People are buying these as an investment, while at the same time, paying less per month than renting. Plus, we have a bit of a sub culture at the project. We all get together all the time and BBQ and hang out and lie to each other.
Don't think garage condos are a So Cal thing. They are not. In fact they started in Ohio. There are at least 50 other projects like this across the country, and growing.