It absolutely has been outside the realm of acceptable political discourse. Jane Kim, who ran for mayor in 2018, said "The only way to make San Francisco more affordable is not by building a lot more market rate housing as possible, it’s by building as much Affordable and middle-income housing as possible." https://medium.com/@sbuss/no-on-kim-58ef07cf459a#1379

We still have electeds who say it's not a shortage, but an affordability problem. They literally do not believe that building more market rate housing will help.

We almost passed a development moratorium in the Mission in 2015. Public opinion has swung fast in our direction.

In SF it was outside the Overton window.