Personally I think there is appetite for high density SFH. I happily live on a a 50’x125’ suburban/city lot.
However, I have zero interest in multi-family properties. I bet most suburban dwellers would agree with me. Trying to force people I to multi family units is where you’ll meet maximum resistance.
The problem is that you really want to get to an average of 20 units per acre (2,178sq/ft lot) for transit efficacy. I happen to currently live on a 2,600 sq ft lot, but I used to live on even less (in a town house). Do Americans really hate townhouses? Because I loved mine. Of course that's only an average, some people can live on larger lots if some people live in condos.
I know this thread is veering more and more off topic but I'll share our initial experience in a townhouse and why we didn't particularly care for it - and why many middle class/suburban Americans probably turn their noses from them.
Our townhouse was a place we wanted to escape from. It was poorly constructed (1), with little to no usable outside yard (2), not particularly convenient to anything (3), and the neighborhood wasn't the worst place but also wasn't really filled with the best people (4).
1) Our area actually has a decent stock of townhouses, on paper at least. Most of them were built in the late 80's/early 90's with bottom-of-the-barrel materials. This seems to be true of a lot of townhouses that I've come across that were built between ~1985 and ~2005. It's more or less the same story with all bulk construction of the area, including condos and apartments to be honest. Many of them were built with the cheapest windows, roofs, plumbing (a LOT of polybutylene), sheetrock, etc. All of that needs to be replaced but the form factor and the shared nature of a townhouse means that you're usually disrupting your neighbors (our outright have to coordinate with them on roofs, driveways, siding, etc.). Many people choose a townhouse because it's the closest thing to a SFH that's not a SFH, so you end up with a lot of people who have expectations of SFH level privacy and will complain about the smallest thing that disrupts them.
2+3) Our old neighborhood actually had quite a few kids. But you never saw them, because the backyards were, on one side of the street (ours), a 4% - 10% grade down to a wooded area. Lots of ticks, mosquitos, groundhogs, and poison ivy. Streetside, the road has a ton of blind corners, some of the neighborhood doesn't have sidewalks, and those that do, the buffer between the sidewalk and the street is barely 2 feet. There are no neighborhood playgrounds, and the nearest grocery store is a 20 minute walk. To better illustrate - the school is half a mile away which for any other SFH neighborhood would be considered walking, but our kids were bussed because it was generally considered too dangerous to walk. That's mostly the story with the majority of townhome neighborhoods here - they're designed to fit as many units into a plot of land without care or consideration for how the properties are actually going to be used or how accessible they are to anything. We were actually lucky that we had a grocery store that's walkable. All the other townhome developments in the area have, at best, a gas station within 20 minutes. That's not to say that SFH's away from town fare any better, but the goal of dense housing should not be to be the cheapest thing available.
4) That brings me to the biggest reason we left - the neighborhood wasn't the greatest place to be neighborly. It and most of the other townhome developments in the area are some of the least expensive places to live that give you a garage and any semblance of outdoor space. If you search our area on Zillow for 2+ Bed 2+ Bath homes, it's our and its sister developments that come up under "least expensive". It's also full of renters, who are not apt to keep up the property. While there are some very nice people there, and plenty of folks do well to maintain their properties, you have a weird mix of unkempt properties on the brink of dilapidation next to well maintained little yards and gardens. Some folks in the neighborhood have zero respect for others' privacy and will let their family issues linger in the air for all to hear.
I don't want to denigrate those who can't afford to live in a SFH, or to own a townhouse, or who are going through struggles. The last point is illustrative of why I think dense housing is so unpalatable to most Americans who grew up in and around suburban areas - we (I speak for a few others in my life, even if folks here don't share the view) have this view of dense housing as a "place for the poors". That's a terrible way to look at it, but that's sort of been the way I've thought of it until the last couple years. I've tried to be more empathetic to the issues that cause folks to struggle with their lives but the fact remains that it's the image that is projected by these communities. They are the places that people who can't afford a SFH live in, especially if there are few apartments available.
Ironically where we live, there ARE few apartments available. Those that are available are mostly 'luxury', where rents exceed the average rent or mortgage of local townhomes and condos. It's like this where I grew up, too. And apart from envisioning well-kept NYC brownstones or historic Philly rowhomes, it's what I see (or at least did) when I picture dense housing.
That image is certainly changing - there have been plenty of luxury townhome developments in my area recently, let alone luxury apartments. But those still miss the point - they're still in the middle of nowhere for the most part and ironically are the very reason our area is having s bit of a housing crisis. The influx of luxury units has led to developers purchasing many rowhomes in the city (all of which are from the 1800s/1900s) and gentrifying the area, driving the people who can no longer afford the renovated structures to the outskirts of the city and into the cheaply built townhouses and apartments that I'm citing here.
That push is leading to more farmland being gobbled up and turned into $450k+ 4bed SFH's that are accessible to exactly nothing, further perpetuating the very problem that we're discussing in this thread.
I think that leads me to the uncomfortable feeling I get when we discuss the "ideal neighborhood" (I've eaten through most of Strong Town's, Not Just Bikes, and Climate Town's catalogs) - our culture doesn't want to deal with the elephant in the room - that these ideal neighborhoods are designed without those who struggle the most financially in mind. Or, at least in practice they don't. We kneecapped ourselves years ago by slapping townhouses, condos, and apartments up in such a way that a car is still required to live there. And the demographic shift into those communities has soured the idea of many suburbanites (especially families, who often have kids and who want a safe place for kids to play [not referencing the demographic, but the poor and dangerous layouts of the neighborhood]) on the idea that it would be a great alternative.
When we lived in the townhouse, our initial next door neighbors moved out. We hoped and hoped that a young family would move in, but instead it was a single guy in his 30's who spent tons of time working on his boat and bikes. He was a really nice guy, and was very respectful, but we had to keep our kids away from his garage and that meant that they were mostly inside during the day. It took us 45 minutes to walk to the nearest park, so we (my wife) often drove (can't fit an infant and two little kids into a bike trailer when you have one adult).
I guess I just don't know how you would sell the idea that a dense community is better for people, without completely outlawing single family construction. So many people we know in the area feel the same way about the townhouses and condos, and even if that same sentiment is prevalent in 20% of the similar areas in the country, that's still tens of millions of people who would prefer the comfort, privacy, and safety of a suburban SFH neighborhood.
Also ETA, more relevant to this thread - a lot of the older townhouses (before 1990) are on 100amp service, and the service lines are underground, and the older ones also don't always tend to have garages so installing EV chargers is going to be difficult to impossible depending on how the property is configured.