Is that necessarily true? I'm a more optimistic about gradual densification. Across the US, we've seen an increase in offices moving to the periphery of cities [1]. I think we keep reinventing mini-cities in the suburbs and will eventually end up with an American-style polycentricity, especially in the South and West [2]. Remote work will increase these pressures.

Let's look at the sprawling suburbs of Houston, Texas. These suburbs have necessities covered within 10-15 minutes by car. If you look at this map [3] and this one [4] of a newer neighborhood in Katy, TX (about 30 miles) from downtown Houston, you'll notice a few points:

* The schools and stores are already close to the neighborhoods. Biking to the store takes ~12 minutes vs 8 mins driving
* It's ~4.5 mi (7km) to the park & ride. Biking takes ~22 mins vs 12 mins by car.
* There's several food places, dentist offices, and doctors offices along the way.

This neighborhood is following the same developmental pattern as the earlier neighborhoods, which some iterative refinements. Of course there is still some low handing fruit that could be addressed:
* This area could add bike lanes whenever they did planned road expansions (which is often)
* Add safe bike and pedestrian over/underpasses for the freeways & busy intersections
* Connect existing paths that connect neighborhood amenities (i.e. parks, schools) to inter-neighborhood paths
* Prevent commercial and industrial site boundaries from harming neighborhood inter-connectivity

These fixes would allow an extremely car-dependent area more "transit options" at very little cost. These would not require rezoning, rule changes (i.e. parking minimums), or forced increases in density. The market repeatedly identifies that people want the same things basic things nearby. But the chosen zoning and local car-centric ordinances perpetuate this car centrality. Parking minimums set a floor on store size, which limits store density, which undermines convenient access by any means other than cars. Builders don't know how the commercial sites are going to be used and exactly what-for.

Within the neighborhoods, access to locals schools and parks are considered in the planning stages. That's why it's common to see schoolchildren riding their bike or walking home from school in groups -- sometimes with chaperones / crossing guards. It's designed to be convenient, for example adding shortcuts between streets to the school [5]. Making these slightly larger to explicitly accommodate bikes, especially for accessing nearby essentials is not a tough sell. This is largely a consequence of builders' presumptions about homeowners' expectations/preferences. It has taken a while, but these same builders are finally starting to run fiber alongside or instead of coax to these newer neighborhoods -- a convenient selling point post-covid.

Regarding densification, there are already apartments [6] built nearby the highway, adjacent to these new neighborhoods. Changes that would require more effort than the points mentioned above include:
* Allow duplexes and small apartments to be built within the neighborhoods
* Apartments and duplexes [7] are currently like standalone "communities," isolated from the surrounding neighborhoods
* Let small shops and offices be built within the neighborhoods, not just immediately adjacent

Note that a lot of these zoning changes only require changing builder presumptions. Often they're building in unincorporated areas. You can see an increasing mix of home-types and nearby shopping in very new communities like Bridgeland [9]. There's even a "desired path" emerging behind this Lifetime Fitness [8]. This path isn't even possible in the older neighborhoods. Basically, builders are rezoning large areas (often displacing cows), so better inter-mixing of stores and community centers (for transit stops) can be done ahead of time.

That's why I don't think the changes required for more transit are so significant.
Transit agencies are already using existing parking (e.g. stores and theaters) for park & rides. To be clear, I personally know people taking park-and-rides to work at Oil & Gas companies because it's more convenient. Expanding access to these facilities, adding some transit interconnections between suburbs, and expanding to important non-office destinations (malls, community colleges, and airports) are low-risk expansion opportunities. Adding compelling optionality can be a means to build support for more expansive projects later on.
I think if builders thought adding autonomous trams through their master planned communities would help make them more money, they'd do it in a heartbeat.

If you look at a older part of the suburbs (south of I-10), you see the same sidewalks and shortcuts for access to the school. But somehow they haven't extended the walking/biking infrastructure to the shopping center across the street from the high school [10].
Even further south, you see the same thing [11]. Sidewalks will connect you to the park, but it's impossible to that Target from the neighborhood directly adjacent! These shortsighted mistakes are (slowly) being remediated with each new neighborhood built. We can achieve substantial emissions reductions by enabling families to get by owning only 1 vehicle instead of 2, especially if those vehicles are EVs or Plug-in hybrids. Hopefully we'll even see more innovations like shared heating / cooling for whole neighborhoods, like this one in Austin [12], while we aim for ever-lower emissions.

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[1] https://www.forbes.com/sites/jackkelly/2022/10/06/moving-off...
[2] https://journals.sagepub.com/doi/full/10.1177/23998083209512...
[3] https://www.google.com/maps/dir/Stockdick+Junior+High+School...
[4] https://www.google.com/maps/dir/Stockdick+Junior+High+School...

[5] https://www.google.com/maps/@29.8434568,-95.7820818,121m/dat...
[6] https://www.google.com/maps/place/Brea+Luxury+Apartments/@29...
[7] https://www.google.com/maps/place/Greenbrae+Ln,+Cinco+Ranch+...

[8] https://www.google.com/maps/@29.9310744,-95.7259749,113m/dat...
[9] https://www.google.com/maps/place/Bridgeland,+Cypress,+TX+77...
[10] https://www.google.com/maps/place/LaCenterra+at+Cinco+Ranch/...
[11] https://www.google.com/maps/place/Meadow+Lake+Park/@29.59629...
[12] https://www.whispervalleyaustin.com/why-youll-want-to-live-i...