Building up destroys the desirability of places. No-one wants to live in cypherpunk environments. See https://www.clemensgritl.com/video
Building 4/5 story buildings with units for families is enough for healthy urbanization.
We have a serious problem in talking past each other though. When people talk about building density the conversation starts around skyscrapers (bad) like Hong Kong or something, but what we need is just medium-density, mixed use development so lots of single family homes, narrow streets, walking/biking, and of course town houses and apartments so we can get variety and mixed income levels living in the same place. The rich family has the giant house on the corner. The young couple fresh out of school lives in an apartment down the street. They see each other every day at the coffee shop or at the park in the neighborhood, or maybe even a local church, gym, or office.
And in building this way we can weave in healthy natural aspects, trees, flowers, gardens, etc. and animals that are better adapted for these environments can live or "visit" these areas. Then as you get further away from this town/city you just get more and more hills and countryside and independent farms.
We know how to do this. We choose not to. It's not profitable for Mercedes if we all walk to work. It's not profitable for Conagra if we grow our produce or buy from an independent farmer. Not that these companies are necessarily (although sometimes they are) evil or anything, it's just an incentives alignment. And unfortunately government officials literally just do not understand what we need to do, so they're like empty vessels chasing things like Sidewalk Labs in Toronto or the Smart Cities Challenge in Columbus where all it amounts to is a corporate handout because the only way to solve a lot of the problems we have is just to build correctly. No amount of EVs fixes our problems (I have an EV btw). What does fix our problems is when families have 1 car per family instead of 2-4, and 90% of their day-to-day activities are within a short walking distance. We need a lot less of this giant SUV to Costco 30 miles away because you're cosplaying living in nature attitude.
This is what an appropriately dense city looks like:
https://twitter.com/trad_arch_bdays/status/15171411856676003...
This is what a correct neighborhood looks like:
https://i.pinimg.com/originals/37/9b/26/379b266652e0a2013c0c...
This is an anti-pattern. It’s devoid of life.
https://facts.net/wp-content/uploads/2020/02/edward-he-uKyzX...
This is also absolutely dead. There is no nature here.
http://media.beam.usnews.com/70/0d/89b92a674c3b894107a03641e...
Idk what it looks like yet but I'm going to figure out a way to fix this.
Even in Shanghai there's plenty of neighborhoods full of life at a human-appropriate scale. Just not at city center.
I question whether we should even have cities with 30 million people. That's probably a problem too. People like to point to what appears to be lower c02 emissions, but that's not the only metric that matters. Metrics that I care about would be something like independent farmers per-capita, bikes per-capita, distance of travel for produce, etc.
> People like to point to what appears to be lower c02 emissions, but that's not the only metric that matters.
On that note, central business districts & skyscrapers aren't actually that great environmentally, although the city model as a whole is much better environmentally than their suburban counterparts.
And it's certainly possible to build a dense, urban city housing even millions of people without a massive central business district. I think, more than anything, the central business district is an artifact of how we organize ourselves economically (IE the economy is dominated by relatively few massive corporations). This is harder to change but certainly not impossible.
When people left the military they went to familiar environments. You "paid your dues" just like a private did. You stayed with the same company. Etc. But that's all changing. Historically that was not the case (well historically we didn't really have companies for that long, but you get the point). So I think we will revert to a more natural flow, which is more decentralization and fragmentation. I think this is inevitable, but I wish/hope/want to avoid the waste of resources in creating these things in the first place.
https://www.fotocommunity.de/photo/plattenbau-dessau-tobias-...
... which clearly is not what encourages building a community like you imagine.
Before someone comes and says that I picked the worst image I could find ... nope. This is the standard for "affordable multi-story apartment housing" in my rather affluent country. In many parts we actively demolish them because no-one wants to live there (location is often semi-suburban) and because they are breed a social-problem-area.
These are just some random examples in Paris. We should build more like this. We can. There are no barriers. None.
https://bonjourparis.com/wp-content/uploads/2016/03/Montmart...
https://www.girlsguidetoparis.com/wp-content/uploads/2014/08...