As an outside it became apparent that moving to SF/SV would be a challenge around ten years ago. There are a number of post on HN from "back in the day" that discusses this topic e.g:
9-10 years is about right. 2005, I had a one bedroom for $1700, and in 2008 I moved into a studio on Twin Peaks for $1300/month. Both were high but still affordable. By 2011, a 2 bedroom in SOMA was $3000/month, and by 2014 it was $4500/month.
This coincides with when tech companies started popping up in SF, instead of South Bay where they traditionally went to.
Are you sure it's tech companies? In 2006 I was paying (part of) $2800 for a generous sized two bedroom apartment in the East Village of Manhattan. At the beginning of 2010 when I moved out the landlord wanted $3500. Today it's going for for $4400.
That's a 25% increase in 3 years and then another 25% increase over the next 9 years. And there was no, or at least only minor, tech company factor in NYC.
This coincides with when tech companies started popping up in SF, instead of South Bay where they traditionally went to.