Here is a USC study on the major demographic changes in the Los Angeles metropolitan area between 1960-2000.

Good reading, no fluff, just facts and numbers.
You draw your conclusions.

Here is the study:http://www-rcf.usc.edu/~dowell/new/changes.htm

Back in 1960, fully 80% of LA’s population was non-Hispanic white, with small minorities of blacks (7.6%) and Latinos (9.6%). Subsequently, the white population has declined in share, dropping to 53.3% of total residents in 1980 and 32.1% in 2000.