(Before anything, let's be clear, the premise of the OP is completely wrong. Secondly, the cheapness of Sunset has nothing to do with whatever Asian-American community lives there, and by extension the whole analysis of 'wanting to live near Asians' is off base and is not only misguided but also disturbing. I digress. )
As an SF native, I'm not so enamored with being "in the city" like a lot of people who move here from other places; it's laughable how irrational some people (and businesses) are about being in SF. Frankly, there are only really a handful of 'nice' places to live and be in the city -- but the niceness is quickly lost by the huge inconveniences of monstrous traffic, overcrowding, parking tickets, relentless fog, gentrifying hipsters, and various other things.
In fact, there are a number of locations in the Bay that are much more cost effective, convenient, and in good earshot of anyplace you need to get investor/talent attention. San Jose comes to mind, but it can skew a little rough and has a 'mini Los Angeles' feel to it not to mention warmer. You can also take the light rail from SJ to Mountain View, which in terms of start-up connectedness is probably more well-connected than even San Francisco. MOST tech companies are still in the Valley; you get a lot of them clustered in Redwood City (Oracle, Facebook, EA), Palo Alto/Menlo Park, and Mountain View (Google, Microsoft). More high-tech companies are in Santa Clara (Intel), Sunnyvale (Yahoo) and San Jose (Cisco). Which is why southbound traffic out of the city is always worse than inbound traffic -- everyone wants to live in the city but a large majority of people work in the Peninsula/South Bay. Why not live closer to work? Well because there are so many 'hip' bars, restaurants, and events in SF -- urban living!
All things considered, I wanted to chime in on the Sunset thing. You're under the impression that the Sunset is some super Chinese/Asian neighborhood -- which first and foremost is more likely an exaggeration or a skewed cultural bias on the author's part.
Considering the makeup of other neighborhoods, and despite there being a handful of asian-y shops on Judah and Taraval streets (main commerce areas in the Sunset) it's not as "Asian" as Japantown, Chinatown or even Daly City. The Sunset is full of older "white people", Persians, Mexicans, Russians, Indians and a number of SFSU and UCSF medical students (especially being that UCSF is right on what you might consider the edge of the Sunset).
In reality, you see a mix of people walking around the street and nothing to really give you a sense that 'oh! this is a Chinese neighborhood'... IT'S NOT! The author, as I mentioned, grossly exaggerated from his own perspective bias.
No, the REAL reason why the Sunset is "undesirable" (cheaper) vs other parts of the city -- and to be clear that statement is very thin -- has more to do with its geography than anything else. Sunset is super suburban and not nearly as "hip" as downtown with its sea of rolling houses. There isn't as much to do and it generally takes at least 30-45 minutes to get downtown on public transportation. (This by its very nature goes against the whole point of being in the hip-urban-center-of-the-universe that is SF, this part of SF doesn't feel very sexy)
If you want to drive there's usually too much traffic on the main streets in and out and when you do make it out the only immediately interesting things to do get old very fast and are still hard-ish to get to.
Finally, throw in the fact that it's easily the coldest area in SF to live (see Microclimates http://www.sfgate.com/bayarea/article/Weather-as-varied-as-t...). There is fog almost all day long, all year long, and temps occasionally get above 60F but are closer to sub 60F even in the summer! The beach is usually too cold to deeply enjoy, and the water is consistently icy. (Ironically, I often ask myself why it's even called the Sunset without it ever having very much sun... we should rename it to the Fogset.)
So, there is no solid draw to the Sunset. It's mostly Blah! That's a good way to put it: blah! July in the Sunset often feels like it does in January.
While the Sunset is not the most desirable place to live it isn't one of the worst either. No, The Richmond District, Tenderloin, Silver, Crocker-Amazon, and Hunter's Point easily snatch that crown away from Sunset faster than you can blink. They have much deeper problems -- mostly crime, inaccessibility, and general remoteness. Living in these areas is much cheaper than living in the Sunset, so if you are all about living in SF on a dime consider those rougher neighborhoods.
Despite the inconveniences of Sunset it is still mostly safe and suburbia-quiet. It is probably a better 'value' in terms of what you get for your money.
But I'm all down for moving somewhere else, starting-up and living better. I'll be back for the next down; this up is killer.
Sidenote: I can't think of ANY place that I have ever been to where people avoid a neighborhood because of the culture there. The nice thing about California is that it really is a diverse place, moreso than you'll se in a lot of other parts of the country. While not all cultures mesh well together, it is generally inacceptable to avoid cultures. It's usually things like crime, blight, weather and inaccessibility that make neighborhoods undesirable.