This has been going on for many years. Community cohesiveness was broken by internment during WWII. Since that time, Japanese have become so integrated with overall California society, they no longer think of themselves as a separate community

Few Japanese are still farmers, and so many others have abandoned their pickup trucks full of lawn mowers to the Mexicans. A great many are employed in technology, and many have married outside their heritage.

The Koreans are much more recent, mostly due to Christian Missionary efforts. They are more cohesive, and nearly all of them share the surname Kim.

Several long occupations by the Japanese, and use of Korean slave labor during WWII have familiarized the Koreans with Japanese culinary traditions. Seeing neglect of these traditions and Japanese businesses, they've been happy to step in.

Where I live, in La Crescenta / Montrose, cultural evolution continues.

In the 20s this was a sort of artist colony, and hosted a couple of notorious sanitariums. Then the Germans moved in, with full dress Nazi rallies held in what was then Bismark Park. WWII put an end to that, but there's still a strong German presences in Montrose, including a very popular boutique sausage maker and a large annual Octoberfest celebration.

Then much of La Crescenta was taken over by extreme right wingers, a few of whom still remain, though most have died out. They were allied with the motorcycle gang culture up the hill in Tujunga. The motor cycle shops are now gone, and Tujunga is mostly occupied by folks who work at the studios in Burbank.

In the '60s and '70s La Crescenta became a community of young marrieds bringing up kids. I moved in here towards the end of this era, 50 years ago.

At that time the Armenians were taking over. The Armenians are few now, most who were here have moved to more upscale communities, while nearby Glendale remains the Western Capital of Armenia.

The vacancies left by the Armenians were quickly filled. Now La Crescenta has become a sort of midrange Koreatown, with Foothill Blvd (the only main street in this valley, lined with Korean businesses, banks, markets, and academic and musical tutoring establishments.

I am now seeing a small influx in Indian garb around here, so perhaps that's the next wave, as the Koreans become wealthy enough to move down the street to La Canada Flintridge.

A decade ago, the remaining right wingers were quite vocally pissed off about these ethnic changes, and tried to get legislation passed that all business signs must be in English - but attrition due to age has been pretty severe. Most of their businesses have closed.

Other regions are also experiencing rapid evolution, especially notoriously Republican Orange County. It was formerly part of Los Angeles county, but broke off due to cultural incompatibility.

There was a huge influx of anti-communist Vietnamese, but the young Vietnames have little interest in that - they're too busy making fortunes running major import/export businesses with Vietnam, Thailand and China. Mexicans have also flooded in.

The faithful Republicans are now declining rapidly, as Orange County increasingly resembles the multi-cultural environment of Los Angeles County.