The plain truth is that the housing crisis is a combination of too much sudden demand fueled by the tech boom and too little supply. The tech community likes to deflect criticism of their sudden influx of relatively high-income workers and say "don't blame us, it's a supply problem."
This bill focuses mainly on juicing supply by removing restrictions on builders. But part of that is weakening the affordable housing restrictions on them.[1] The problem with that is, increasing market-rate housing alone may not make an appreciable difference in prices where it matters most from a macroeconomic perspective: for low-to-mid income residents.
Cities need teachers, service industry workers, artists, etc. Already the restaurant industry is facing a major worker shortage.[2] Let's not even get into the cultural effects of long-term residents getting displaced en masse. So if market-rate supply alone can't solve this, then you need affordable housing regulations to set aside spots.
Sam has offered a rather simplistic statement on the law of supply and demand on this. But that masks the real question: whether weakening affordable housing demands as this bill does is a smart move. Will juicing mostly market-rate housing be enough?
[1] http://48hills.org/2016/05/22/a-terrible-housing-bill-looms-...
[2] http://www.bizjournals.com/sanfrancisco/print-edition/2016/0...