@Vasundhara Ranjani people invest a lot more than that into the San Diego market for a lot less return believe it or not. For many, its not about the returns. Like us here on BP, they think real estate is a secure investment and instead of having it in the market, they rather have it in real estate and can take advantage of the tax benefits of this asset class. In an A class area you can also count on rent appreciation over the long term so that 3-4% return will increase as you pay down your debt and rents go up. Sorry all that to answer your last question.
As far as risks go, A class properties do have risks. The main risk I see, when the economy is in a downturn, A class properties are the first places people will leave. Its a luxury lifestyle but people don't need to live there. It's why most syndicators are targeting the B and C class property types. Most can still afford to live there and in this market cycle you can't afford to build them. Its why across all of the U.S., C class apartment complexes have less than a 4.5% vacancy rate.