"The only thing you have to do to build a traditional city - an environment where people naturally want to walk - is to build Really Narrow Streets; "
Then pictures of several architectures of buildings are shown along very narrow streets, but nothing more than 4 stories high.
My first thought when I read this was, the narrow streets constricts the heights of the buildings possible because if the buildings are taller than a few stories, the windows will not get light and there will be lack of wind, fresh air and sense of openness. When every building has to be short, how can you meet the demand for housing? Perhaps I'm biased because I live in Jersey City, across from NYC with its own share of residential high rises. Where are you going to house all the people who cannot afford to have a place to stay, due to high cost of housing, due to low supply, due to short buildings?
WRT zoning I've lived in three places with that strategy and none really worked.
One is Madison WI with pedestrian only State Street. If the experiment of State Street worked, it naturally should have spread thru the city, or at least thru downtown, over the course of many decades. Instead its mostly avoided other than sorta being an outdoor strip mall of bars, sorta. I dread going there because I no longer live there and know how unfriendly that design is to visitors.
Another example is the small boring river city I grew up in, with legendarily bad downtown street layout, loops of one way streets and no parking and narrow streets and everything a meandering unpredictable cowpath so easy to get lost, aside from only having 4 bridges over the river which cut thru downtown and the river isn't even navigable anymore. It just didn't sell and resulted in economic decline. All economic activity has always pushed out of the downtown into the areas nearby the interstate with easy parking and nobody who could afford it would voluntarily live there. People just didn't like it.
The 3rd example is I live in a suburban neighborhood about 50 years old which was intentionally zoned into quiet (admittedly large) pure residential, narrow (for suburbs) streets, and within short walking distance (oh, maybe a quarter mile) the perimeter of the subdivision is encrusted with retail and commercial and light industrial along major arterial roads. This seems an utter failure in that noone commutes by foot or bike, but I certainly see a lot of cars. In theory this should work, in practice it doesn't. Some of it is expense driven. There are 3 restaurants I could walk to in 10 minutes, but why blow the money on one of three if a 15 minute car ride puts me in reach of way over a dozen restaurants, many of which are better than the walking distance only competition? These arguments all seem to devolve into all retail/service is interchangeable commodity... the marketplace disagrees and prefers choice and competition, even if it requires personal automobiles. If I wanted to only visit 3 restaurants and 2 bars because thats all thats "within range" I'd live rural and cheap, not city prices, especially when the claim is city life means you get a better selection.
There is the meta problem, that in an area with decent public infrastructure, I can work 20 miles from home in a 20 minute commute in my comfy car. In NYC thats what, a couple hour commute in a mix of foot and public trans? I could do it, but the hit to my standard of living would be brutal. Either I'd spend all my life commuting which is a waste of a life, or I'd have to work within a 20 minute walk, which would be incredibly inefficient and I'd be stuck doing manual labor or something like that. Another thing thats rarely discussed but very important is commercial density vs residential density. I work in a 800 person building, and even if you could fit 800 tiny little houses within a short walk, if I got a new job I'd have to move which would be a PITA and we're assuming only a single breadwinner per family, what if we lived within walking distance of my wife's employer not mine?
This is something the OP doesn't discuss well. The "traditional city" provides a sense of beauty and "place" for the tourist, but it's an annoyance for people who live there. Housing gets expensive, quality goes down over time, and building up becomes impossible. Living without a dishwasher, as one might have to do in old housing that can't be economically upgraded, gets old really quick. That's not to say that "traditional city" equals "no dishwasher"; I'm only pointing out that there are some serious hassles (noise, expense) to that way of living.
The driver-centric planning of the US is pretty terrible, because cutting your urban land with ribbons that are dangerous to cross, unpleasant to look at and hear, and utter non-places turns out to have catastrophic effects on urban life, even in objectively great cities like Chicago and New York. I will agree with that. I don't think that four-story buildings and narrow streets are a workable solution. That will just make everywhere decent unaffordable, so you'll need transit or large towers nearby anyway to keep the local economy from falling to shit in bad times.
What we've learned about the car is that it scales horribly. Robert Moses re-designed cities for the car because he was an elitist asshole. At that time, most working class people didn't have cars. "Parkways" were thus named because he intended them as actual motoring parks (for rich people). In the 1940s, cars became affordable to average people and promised to "disrupt" urban landlords-- a hard thing to oppose, as anyone who's lived in New York or London will agree-- by making previously useless land livable. However, we found out that when everyone drives, the result is congestion, misery, pollution, and actually surprisingly expensive. Between insurance and gas and maintenance and parking-- and the suburbs actually failing to be affordable except far away from urban centers and jobs-- the car became the new landlord in suburbia.
I agree fully with OP that suburbia is ill-planned (who doesn't?) and that car-centric cities are a mistake. But the 21st century is going to call for something new and transit will have to be a big part of it. Personally, I think we should tax the tits off of landlords and real estate owners (beyond one house, owner-inhabited) and use the money to build a first-rate rapid transit system. Since their wealth comes directly from inefficiency of geography, we should tax them to pay to fix that inefficiency. It's only fair that those who benefit from a bad situation be called upon to pay to fix it.
My first thought when I read this was, the narrow streets constricts the heights of the buildings possible because if the buildings are taller than a few stories, the windows will not get light and there will be lack of wind, fresh air and sense of openness. When every building has to be short, how can you meet the demand for housing? Perhaps I'm biased because I live in Jersey City, across from NYC with its own share of residential high rises. Where are you going to house all the people who cannot afford to have a place to stay, due to high cost of housing, due to low supply, due to short buildings?