"The population is also growing. From 2000 to 2010, 28,500 new San Franciscans arrived in the city. From 2010 to 2012, the city welcomed another 20,600 inhabitants in just three years."
Oh, is that all? I live in Austin, TX, the #1 destination in the U.S. for people aged 25-34. [1] You got 28,500 people in 10 years? We get that many new people every year. In fact, perhaps even as often as every 6 months; 158 people move to Austin every day by another estimate. [2]
You have to increase the supply of rental and housing units in order to accommodate population growth. Austin is struggling with it, too, but condos are springing up downtown.
San Francisco has no choice; Austin is barely managing to handle the growth, and we're a growth-happy boom town teeming with young folks. (Yes, it's pretty awesome to run a startup here too--I'm having a blast!) You must build more housing. If you are an SF resident, vote people in who will support new housing. Vote out the politicians who curb growth with ridiculous laws. Otherwise, all the cool people will end up in Austin (and other cities that can better manage the growth. ;)
[1]: http://www.statesman.com/news/news/local/for-people-on-the-m... [2]: http://www.realtyaustin.com/blog/how-to-keep-up-with-158-peo...