In the extremes I fear this would lead to Dredd-like Mega Cities just taking over the entire continent. At some point, a lot of people want a multi-generational space to stick around in for a long time (where the sun isn't blotted by tall buildings). Tearing up suburbs for skyscrapers every generation can't possibly be "the answer..."
This take makes no sense, if you take into account that 100 families could live in the space of one single detached home. High density building isn't suddenly going to take over suburbs like that.
That’s a huge exaggeration. Tall buildings require a much greater footprint than a single detached home.
Knock down three adjacent homes and you can get maybe 6-8 levels, which would be no more than 40 families.
Have you been to any place other than the US? The size of a single detached home, including backyard, front lawn and sides can perfectly fit an entire 5-8 story building of two 80m2 apartment per floor, if not more. If you live in a well designed city with public transport, you don't need to waste surface area on a parking garage.
The key is always setbacks - if you have to have ten feet on each side of every building, you can only get "so dense" without going for apartments that consume an entire block.
The problem is introducing the zero-setback designs organically - as the people there likely receive little to no benefit, and the people who do receive the benefit aren't there now.
E.g., a house could easily be fit between mine and the neighbors, but we wouldn't really benefit from the density improvements, and the family that would move into the "missing middle" doesn't currently exist here.
I'd love if our lot was zero setback, as I'd build an addition right up to the property line instead of having to try to find another lot/house in the area we want.
It needs to start somewhere though. Obviously you can't just drop a single building in the suburbs and call it a day, it should be many, with plans for public transport, axing the zoning code to allow for the ground floor of the building to be used for comercial purposes.
Average density in an urban core (North America) is like 90 residents per acre, vs like 5 res/acre in suburbs. Not a very big exaggeration
Population is generally stable or declining out side of the developing world.
Infinite cities only yh happen with infinite population.
It's declining nearly everywhere except for some portions of Africa (where the trend is also towards lower fertility. I'm not aware of anywhere that is both "stable" (~2.1) and has a flat trend; that is to say that it isn't just momentarily passing through stability on it's way to declining population.
There are many types of houses in between suburbs and skyscrapers. This is "missing middle" housing. Duplexes, townhouses, small apartment buildings, etc. Look at Old Town Alexandria, VA on Google Street View, for example.
> lead to Dredd-like Mega Cities just taking over the entire continent
This is impossible. Look at even the densest cities today such as Hong Kong, with many 50-storey buildings packed closely. HK as a whole has maybe 25% land area allocated for buildings and the rest is forest and green space.
Or consider Tokyo - sure, it is a big sprawling metropolis and pretty much an uninterrupted patch of concrete. But the urban area does eventually end, and much of the land area of Japan is mountains, forests, farms, etc.
That cannot happen. Cities need a lot of "empty" space around them for farms. Well I suppose everyone could move to Spain (picking a random country) and leave the rest of the world to robotic farms. However we can't expand to cover even all of Spain unless everyone is living in a mega suburb with everyone having their own single story mansion.
(others have already pointed out that populations are on track to fall shortly and there is no reason to think that trend will reverse though nobody knows)
In what extremes? "Extrapolate this forward through five hundred years of exponential population growth that is not in evidence"?