He's one of the Market Urbanism ( http://marketurbanism.com/ ) guys, so a bit more on the libertarian edge of things, but it's a good point in any event: cargo cult urbanism is probably better than "suburban experiment" urbanism, but flexibility and adaptability are even better.
Edit - one of the really cool things about the growing movement that - broadly - includes YIMBY's, Market Urbanists, Strong Towns and so on is that it really crosses the ideological spectrum. For instance, this quote:
"Reforming local land use controls is one of those rare areas in which the libertarian and the progressive agree. The current system restricts the freedom of the property owner, and also makes life harder for poorer Americans. The politics of zoning reform may be hard, but our land use regulations are badly in need of rethinking."
Pretty sure progressives are strongly aligned on opposition to any housing construction unless it’s specifically set aside for low-income residents, and are okay with low density zoning as an anti-gentrification measure.
Are you from San Francisco? I've noticed that "Progressive" has taken on an extremely weird meaning there, which is contrary or at least orthogonal to how it's used everywhere else in the world. Nowhere else that I know of is opposition to urban infill development billed as "progressive".
It's non-uniform there, which is a little weird because "progressives" in the Bay Area are arguing strongly for more infill development while other "progressives" are arguing strongly against new development.
I think it's because San Francisco was "progressive" back in the 60s, which means that there's been time for the past couple generations of progressives to become entrenched NIMBY's with a vested interest in the status quo while still maintaining their "progressive" identity. It's a very weird yet oddly lovable city.
IME it's because SF homeowners have created a narrative that says any new development threatens (and can only ever threaten) rent control. There are many theories--induced demand, Ellis Act evictions, destruction of rent-controller properties--but the narrative is the same.
Therefore, if you're worried about protecting the security of renters (who constitute about 2/3 of residents) and especially low-income renters then unless you know any better the predominate political narrative is to oppose new development.
The narrative is deeply entrenched. For example, the narrative says (among other things) that new development destroys rent controlled properties as any building newer than 1995 is exempt from rent control under state law. But rather than lobby to change the state law to make it easier to expand rent control (i.e. some sort of quid pro quo--expand rent control at the same pace as new development so total rent-controlled units stay the same) people just reflexively oppose new development.
Because homeowners have co-opted the disparate opposition groups, the potential for compromise and novel solutions is stonewalled and never communicated through normal channels (community groups, neighborhood papers, ballot initiatives, City Hall backrooms, etc). All the voters know is to oppose development. Full stop.
It's more complicated than that. The recent Minneapolis mayoral race had housing policy as a major issue, and Minneapolis is nothing if not progressive.
Affordability and gentrification are interrelated, but so is quality. I live in a relatively low-density neighborhood of mostly 80-110 year old houses. Lately, we're getting new development in the form of cheap older rentals being torn down, and large-for-the-lots (typical lots are 1/10 acre) new houses being built. These new houses are considerably more expensive than neighborhood average. My above-average house is worth about $300, but a new house two blocks away just sold for $475k before construction was completed. So I have concerns. On the other hand, that new house replaced a run-down rental. A lot of these old houses simply have worn-out bones and will never be good again. Left on their own, they'll contribute to the neighborhood drifting "bad", with cheap rentals.
And developers? There's no money in building "affordable" housing. They'll build upscale if they can, because it's much more profitable.
What do I want? A better neighborhood, yes, but one where the people who already live here can continue to afford to live here.
Jane Jacobs, one of the historical thought leaders behind modern urban planning, discusses in her book (The Life and Death of American Cities) how thriving neighborhoods have a mix of cheap old real estate and expensive new real estate. The old real-estate allows for places like dive bars, and general affordable housing to exist, where new buildings house chain stores, high end boutiques, and allow the neighborhood to grow to match current demand from new residents.
The key issue here is that this cycle works best in the long term, but can cause pain in the short term. Additionally, if the new housing doesn't match the complete incoming demand for the neighborhood, the prices of the old units rise as well furthering displacement. In turn, she advocated for the removal of zoning, for as it stands right now, there is an extreme demand for housing in neighborhoods that are zoned in such a way that restricts their density from matching the demand in addition to pushing commercial activity to fixed locations where prices will always be high due to demand to living within walking distances to stores.
So there are multiple policy options that you could do.
There's deregulation; deregulate anything that isn't explicitly for safety purposes. Schools and sewers and congestion and all of that should ideally be paid for with impact fees, not reflexively blocked out of hand. Every additional regulation is a cost on the developer passed down to the owner and the renter, and with enough small costs eventually you start pricing people out.
There's also more regulation; a lot of the current appreciation is because America places a lot of strange emphasis on housing as an investment product, rather than a commodity. It wasn't always this way; go back a few decades and property performs more like a bond than a stock, none of this speculation and house-flipping BS. And in most housing markets, housing works this way. Tax or restrict purchases of non-primary homes and such.
And then there's the final thing; lot size regulation. You can cap how big a lot can be for a project of a given size. You could build a very comfortable house at 1/10 an acre, or even 1/20th of an acre; it's hard to justify a single-family house much bigger than that. And in general, buildings should take up at most a quarter of a normal city block.
My neighborhood is old. Lots are generally 1/10 acre, and many houses are under 1000sqf. So questions for us aren't about building new, but rather about how to maintain the neighborhood for the future. How do we replace old houses that are falling apart without changing the essential character of the neighborhood? How can we get some more small businesses and restaurants without giving way to strip malls and big boxes? And the current controversy... there's a possibility that a light rail route will pass within a block of my house, down the major in-out drag for the immediate neighborhood. The light rail does us no good, but because it's a relatively short residential pass, we will have a hard time resisting.
It's kind of a grab bag. Some people get it, some don't. Same on the right - some are aghast at the idea of poor people moving into their neighborhood, others are more "ok, freer markets, that's cool!".
Edit - one of the really cool things about the growing movement that - broadly - includes YIMBY's, Market Urbanists, Strong Towns and so on is that it really crosses the ideological spectrum. For instance, this quote:
"Reforming local land use controls is one of those rare areas in which the libertarian and the progressive agree. The current system restricts the freedom of the property owner, and also makes life harder for poorer Americans. The politics of zoning reform may be hard, but our land use regulations are badly in need of rethinking."
From https://www.brookings.edu/research/reforming-land-use-regula...
Edit 2 if you're interested in Strong Towns, it's a pretty cool group, with Slack ( https://www.strongtowns.org/discussion-board/ ) and local groups that are starting to form: https://www.strongtowns.org/local/