Actually, everything I wrote is a fact, and you can verify it. SF rents went down as recently as 2012, and are currently in a pronounced, acute period of hyperinflation [1]. San Francisco's population declined rather dramatically from 1950-1980 [2]
I'm sorry if this doesn't fit with your preferred narrative, but citing opinion articles does not provide data for your position.
[1] https://medium.com/@mccannatron/1979-to-2015-average-rent-in...
[2] https://cdn.vox-cdn.com/thumbor/2FrCiZiCNaMFiUqWC_RK8sh3NnU=...
/cdn.vox-cdn.com/uploads/chorus_asset/file/4660089/Population-Growth_SF.0.jpg){kind=link}
Edit: even your sfist link confirms the basic facts, despite its (inaccurate and hyperbolic) headline. To wit:
"Dips in the population, urban flight, and a decaying Edwardian housing stock — much of which was built between 1907 and 1910 and was in great disrepair by 1970, when areas like Alamo Square were extremely "low-rent" and dilapidated — may have made life cheaper for the hippies, but that all began to change by the early 1980s."
So yeah...SF hasn't "always" been an expensive city. No more than any other city, anyway.
What is true is that for decades people who came here at some time in the past complain about how newcomers are overturning its way of life, despite having been newcomers themselves at one point.[1] Aging hippies complained in the 80s that yuppies were ruining the Haight, despite having been "neighborhood-ruiners" themselves when they came in the 1960s; the Mission used to be an Irish and Italian neighborhood before it was the center of Latino culture in the city, but it's the neighborhood most vociferously complaining about newcomers and insisting on building moratoriums to stop the neighborhood from changing.[2] It's all deeply hypocritical and unprincipled, but also completely unsurprising.
tl;dr: San Francisco has always been an expensive place to live and we've never built enough housing to meet demand [3]
[0] https://experimental-geography.blogspot.com/2016/05/employme...
[1] https://ww2.kqed.org/news/2014/04/15/san-franciscos-current-...
[2] http://sfist.com/2015/10/07/san_francisco_has_always_been_a_...
[3] http://www.huffingtonpost.com/entry/san-francisco-housing-cr...