• Are these people qualified? How many of those Latino or Asian people speak English or even have an American high school education? I'm in Canada, but my parents for example were refugees who came here in their 20s (and so did many of their friends). Only the ones who spent a lot of time trying to learn English or to get some sort of formal education is really doing anything beyond farm, factory or restaurants. You have to consider how many of them came here without proper english or education because they wanted a better life.
• Are there social reasons why that's the case? For example they talk about Asians, as someone else mentioned there's social reasons for why they might not pursue a career there.

I think as time goes by the offspring of these groups will be more "qualified" and the watering down of social/cultural factors will give that better reflection of California's diversity.