> I think you underestimate the practical difficulties of providing 7 billion people with top-notch public transport and other public services
While some public transport issues increases with density (harder to e.g. dig new tunnels), one of the major issues with public transport at scale is the cost of laying rails and digging tunnels, and amortising those costs over larger populations makes it far more affordable. Once you have the rails, density means you can offer far more frequent service, which makes a huge difference to users. Being able to just assume there'll always be a train within a minute or two is a huge deal to get people to actually use public transport. Density also works the other way and reduces the need in many cases, as well as drop delivery costs and give new options (e.g. I can get stuff from one of the local Amazon competitors couriered over in 2 hours) that first become cost effective when density is high enough to create big enough markets.
> (though there are artists' renditions, most of them dystopian)
That may be so, but density to an extent also creates opportunity. E.g. my local road takes up roughly 45,000 square metres. Of this, roughly 1/3 is gardens where each family in effect only gets use of a very small portion, leaving many of them largely unused. Another roughly 1/3 is pavement, front yards mostly used for bins etc., and the road. Near our local station, new highrises are going up that will house almost the same number of people on a couple of thousand square metres of space. That's a lot of space freed up.
In other words: The question is how far you want to go. If you slash space wasted on roads and wasted duplication, and increase heights, you can get massive increases in density almost everywhere and still end up with more desirable and practically usable space for most people to actually use for things other than transport that is only necessary due to the low density. If you go further than that, and take away all the green space etc., then yes, you get a dystopia.
But you don't need to go very far. E.g. where I live is relatively average density for London. Increase the density of the London metro area five times, and you could empty the entirety of the rest of the UK into London. If every road like mine was replaced with high rises, you'd be able to achieve that with ease and still be left with vast empty tracts of land for new parks (and allotments for those who actually use their gardens today). London makes up well below 1% of the land area of the UK.
I'm not suggesting it'd be a good idea to create a single megacity for the entire UK population. But achieving the density would free up huge amounts of land even if we set aside space for lots of big new parks. It'd also save vast amounts of energy used on transport by cutting distances for most travel.
Pretty much everyone I know in London have moved here willingly, and like it here. I no, I'm not suggesting making it more crowded. I'm suggesting making it denser.
They're not the same.
Taking the current structure of my street and moving in 5 times more people would be a disaster. It'd be tiny little flats and bedsits, no space for parking. Endless queues.
Compressing my street into 1000m^2 of highrise would be a very different matter, and would let you increase density 5-times (so 5,000m^2 of highrises) near the end of the road closest to the rail station and bus station, and you'd still be left with 40,000 square metres of free land for e.g. extra parks and other amenities.
I don't think that'd be more crowded at all - on the contrary. Most work journeys would be drastically simplified and shortened. Far fewer people would need to depend on cars. Dense residential towers close to major transport interchanges could free up massive amount of road capacity, and outright remove the need for many roads even while pushing overall city density up towards Macau levels.
A lot of crowding is created by bad planning that lengthen journeys and force people to take routes that are already busy.
E.g. 15 years ago or so I lived at Marble Arch. I walked Oxford Street to Holborn where I worked every morning. It was relaxing and quiet in the morning. Then the Central Line derailed and there were repair works for weeks. Of course this was not a result of bad planning, but an accident, but it is a good example of the level of impact available transit options has: Suddenly it was as crowded in the morning as during the afternoon/evening shopping rush. (Lack of) crowding is as much a function of well planned transit as it is a function of density.
Plan a city right, and build dense, well located, housing within easy reach of high capacity transport, and it doesn't need to feel very crowded, because the feeling of it being crowded is not down to how many people that are near you, but how many people you can see and hear immediately surrounding you. Reducing the unnecessary roads, and freeing up space for leisure activities that spread people out (e.g. parks) can often reduce the feeling of being in a crowd even if the actual residential space is incredibly compact.
While some public transport issues increases with density (harder to e.g. dig new tunnels), one of the major issues with public transport at scale is the cost of laying rails and digging tunnels, and amortising those costs over larger populations makes it far more affordable. Once you have the rails, density means you can offer far more frequent service, which makes a huge difference to users. Being able to just assume there'll always be a train within a minute or two is a huge deal to get people to actually use public transport. Density also works the other way and reduces the need in many cases, as well as drop delivery costs and give new options (e.g. I can get stuff from one of the local Amazon competitors couriered over in 2 hours) that first become cost effective when density is high enough to create big enough markets.
> (though there are artists' renditions, most of them dystopian)
That may be so, but density to an extent also creates opportunity. E.g. my local road takes up roughly 45,000 square metres. Of this, roughly 1/3 is gardens where each family in effect only gets use of a very small portion, leaving many of them largely unused. Another roughly 1/3 is pavement, front yards mostly used for bins etc., and the road. Near our local station, new highrises are going up that will house almost the same number of people on a couple of thousand square metres of space. That's a lot of space freed up.
In other words: The question is how far you want to go. If you slash space wasted on roads and wasted duplication, and increase heights, you can get massive increases in density almost everywhere and still end up with more desirable and practically usable space for most people to actually use for things other than transport that is only necessary due to the low density. If you go further than that, and take away all the green space etc., then yes, you get a dystopia.
But you don't need to go very far. E.g. where I live is relatively average density for London. Increase the density of the London metro area five times, and you could empty the entirety of the rest of the UK into London. If every road like mine was replaced with high rises, you'd be able to achieve that with ease and still be left with vast empty tracts of land for new parks (and allotments for those who actually use their gardens today). London makes up well below 1% of the land area of the UK.
I'm not suggesting it'd be a good idea to create a single megacity for the entire UK population. But achieving the density would free up huge amounts of land even if we set aside space for lots of big new parks. It'd also save vast amounts of energy used on transport by cutting distances for most travel.