alt Hacker Newsi appreciate the thoughtful response, and the fact that it’s rooted in a desire to maintain some element of diversity.
i’d play your observation back at you though: there’s more than just young renters and nuclear families in terms of household typologies, and nearly all of the other ones (childless couples, empty nesters, older singles aging in place) would also benefit from ownership (or “rooted”) housing opportunities that things like a quad would provide in these neighborhoods. household size across the US has been shrinking for decades, and there is truly a lot of demand for smaller homes at all stages of life. instead of looking at the quadplex in the SFH neighborhood as a way for “young renters” to displace families out of the neighborhood, it’s an opportunity for other households to take root or make a life transition without having to leave.
if quads in SFH neighborhoods are just being overrun with young transient renters, it probably means there’s not enough “amazon boxes”, and may be related to broken zoning at the upper end of the spectrum.
also, this is all without saying… it is entirely possible for children to be raised in a home that is not a detached SFH! it is certainly a preference for a lot of people, but it is not a hard requirement. and missing middle buildings like the 2/4/6 plexes are some of the best non-SFH buildings for doing that, where you can more easily have 2-3 bedrooms and some sense of a yard.
I think we largely agree on the fact that SFHs should not be the only option for young families or empty nesters or aging couples. (As an aside, all of the above live in SFHs on my block, as well as young single renters in their 20s who share SFHs as roommates). I brought up Baltimore rowhouses for that reason. My Mom grew up in a duplex in LA with a backyard... my brother is raising his own kids in almost an exact copy of that duplex.
I'm not sure what you mean about the lack of new construction of that type coming from broken zoning at the upper end of the spectrum. Maybe uou could elaborate. The upper end of the spectrum in Portland is... almost everyone with money moves to either the oldest exclusive homes in one of two very non-diverse neighborhoods (Laurelhurst or the West Hills), or else they move to the exurbs and build McMansions out in the farmland. Neither is really actively engaged in a community beyond a homeowner's association, and neither is walkable or a place where people of different economic and cultural backgrounds get to interact for everyone's benefit.
So maybe what I'm trying to say is that the high upper end (homes over $1M, let's say), is going to remove itself anyway, and that yes there should be more construction of 2-4-plexes which are not Amazon boxes... but there seems to be no incentive to build those things, and I don't even know how you could do so on a 1200 sqft lot.
In the interim, Portland has eased lots of rules on the use of ADUs and trailers in backyards and even yurts. I bought my home for $450k and the range in the area goes up to $800. This tells you that what I'm arguing for is a working middle class that should have access to living in the city with a modest back yard.
But I do feel like the crusade against SFHs has a distinctly classist, anti-middle-class, anti-family quality to it... and what I mean to say is that it is the working middle class families in the upper end of housing on those avenues who anchor those blocks and keep the neighborhoods livable and loved and who keep the businesses in business. I've seen what's happened to such inner city SFH neighborhoods in Los Angeles, and it turns into somewhere that no one would want to live if they didn't have to, with no community or neighborhood to speak of. Row houses and shared brownstones in East Coast cities have fared slightly better as an attractive living pattern.
Ultimately too, your argument is that not everyone should live where they live, because more people want to live in that spot, so if they want space they should move to the suburbs. My argument is that not everyone can afford to live exactly where they want, either way, but that doesn't logically imply that you should increase density as much as possible in a mixed and vibrant neighborhood just because people want to live there. At a certain point it will lose the very thing that makes people want to live there in the first place. Not even to get into the fact that no one actually works downtown anymore or commutes away from the neighborhood, so this is purely a choice for most people.
You still didn't address my point that every SFH torn down for a 4-plex just redistributes individual middle class ownership to financial corporations.