The "progressives" generally want to limit gentrification, prevent renters from being evicted, and add more subsidized housing. The "moderates" generally want to make it easier to build more housing of any type. You could broadly characterize the two groups as "default skeptical" vs. "default supportive" of real estate developers.
But housing is only one point of disagreement (albeit one of the most significant), plenty of people have more nuanced positions than this, and these camps are not entirely uniform across issues. Other points of recent disagreement include Covid lockdowns, what the school board should focus on, how hard prosecutors should go after police misconduct vs. minor crime, responses to the homeless, how much power the board of supervisors should have vs. the mayor's office, ...
Progressives believe that allowing developers to build housing will only create "luxury" housing that is unaffordable to all but the rich, increasing gentrification and displacement. Therefore it's necessary to mandate things like "inclusionary zoning" and tight review of every single development project.
Empirically, the progressive stance results in a lot less housing of any sort getting built, whether "affordable" or otherwise, and consequently higher housing prices for all but the lucky lottery winners who grab the limited number of BMR ("Below Market Rent") units. Some would say that that's actually the goal of progressives (ie, they're using "progressive" window dressing to preserve property values/neighborhood aesthetics of the very rich).
It's not fair to say that the progressive group primarily consists of "NIMBYs and nostalgic boomers", nor is the group cohesive enough to label anyone's individual comments as representative of a "they"; if you are going to characterize either of these groups negatively you should try to quote specific comments and attribute them to specific people, rather than making vague insinuations.
I think you offered charity to the point of being misleading. There is only one side who wants to make housing more affordable. The charitable view of progressive policy making is that they reject any demand for San Francisco to be a commercial center and want to preserve the lifestyle, built environment, and composition of residents to what it was in the 80s.
20 years ago, progs would admit outright that they thought new development was undesirable. Since, it has become more inappropriate to say that out loud so they dress it in concerns about only supporting housing under economically infeasible conditions.
Folks interested can read what CCHO said about SB35 here: https://www.sfccho.org/in-the-news/2018/10/13/opinion-alarmi...
The crux of their concern/prediction is:
> As currently written, the practical outcome of SB 35 will be to further expedite and accelerate market-rate approvals in the small handful of California communities where the real estate market is already hot – communities that are overwhelmingly urban, low-income, and predominantly people of color. These are the same communities that are currently grappling with displacement and gentrification, and typically have terrible imbalances of market-rate housing development compared to affordable housing. Simply accelerating approvals in those communities is just a recipe to spur even more aggressive gentrification.
I personally think folks like the CCHO are taking a misguided policy approach to solving/ameliorating the problems they worry about, and sometimes behave disingenuously (and should be called out, with specific details, when they do so). But that doesn't make their concerns illegitimate.
Here's an example of an earlier direct reply by Wiener to CCHO about the bill: http://www.beyondchron.org/wp-content/uploads/2017/04/Senato...
> This housing crisis will never be solved without a solution that includes a significantly increased supply of all types of housing, at all income levels, in every community throughout California, both subsidized and non-subsidized. The devastating eviction crisis and rapid displacement of low- and middle-income people from cities results, in large part, from failing to build enough housing for the past half century. SB 35 empowers the state to take action and ensure that every single community is approving its fair share of housing – especially those communities currently punting their housing needs to neighboring jurisdictions.
Here is Calvin Welch, friends with Marti and Cohen and housing guru to Sup. Preston, saying Home S.F., a gentler streamlining measure vs. SB35, was ethnic cleansing: https://missionlocal.org/2016/01/sf-delays-controversial-hou....
I’ll keep looking for the other statement I had in mind.
Calling these proposals "ethnic cleansing" is ridiculous hyperbole. Not as stupid as a death-threat song lyric tweet, but definitely unhelpful. Welch was rightly called out for that one.
It's true that affordability isn't poured into concrete, but it is baked into each and every real estate transaction.
A new luxury high rise needs to have x number of affordable units by law. As you point out, it's true that they don't build the affordable units much or any different than their other units.
But, the way the whole financial side of the thing is structured is completely different than it would be if the laws were different.
A home is just as much a mortgage as it is a physical object.