That's not really accurate. If one insists on living in a new building with amenities, or in an ultra-yuppified neighborhood (e.g. Marina), then yes, the sky is the limit on rental costs and there are no bargains. If you're more flexible, then you can go a lot lower. My last 1BR (in SOMA, on a rough block but the apartment was perfectly nice) was $1100, and another 125 for parking. I have friends who have 1BR and studios in Tendernob, Panhandle, and other decent but less-popular places for around the same cost. Mainly it just takes patience and persistence to nab the deals when they become available.
That said, living in SF on a total budget of 1500/month is going to take some compromises.
That said, living in SF on a total budget of 1500/month is going to take some compromises.