SimCity is a fun game but it's really broken for modelling real world stuff.
SC4 intentionally made it stupidly easy to make the city work financially and also killed what I thought of as "the game god." It's all ooh, shiny and can be fun in a largely superficial manner. But I don't think it works well as an actual city simulation anymore.
(SC4 followed the company acquisition. It has a more polished, corporate feel and it's cool that it has things like recycling centers. But I am not really a fan.)
I cannot find an article about it, but one city uploaded it's data to SimCity and got surprisingly solid city modeling results. This was before the joke that is SC4.
Edit: Geez, can we not downvote the comment I'm replying to? I left out the fact that I primarily play SimCity 3000. It's a perfectly reasonable reply that prompted me to fill in missing details that I hadn't thought to include in my original comment.
I have no problem with that generally because I would rather see downvotes than see every single person who disagrees feel compelled to pile on with petty BS. But in this case, the comment called attention to a defect in my earlier comment -- my failure to specify which SimCity -- and allowed me to add the missing information.
Since my reply with the additional info has substantial upvotes, I think it's wrong to punish the comment that elicited that reply from me. It has too much of that "you win an argument by making the other guy lose" vibe.
I hesitate to say this explicitly, because past experience suggests it will result in a temporary pile-on of everyone and their brother nitpicking the hell out of my comments, but I really don't want to discourage good faith comments that nudge me to address defects or omissions in my comments. I don't think that improves discussion here. I think it makes things worse.
"Don't shoot the messenger."
Also simcity 4 isn't meant to be a 1:1 mapping from game to real city anyway. Most buildings in simcity4 can hold a multiple of what they would contain in real life; it is a model of a city, not a real city, after all. So it stands to reason that they could just cut out the parking lots for aesthetic purposes.
What's the argument for sprawl leading to less infrastructure burden?
There is a lot of money in London, people just can't fathom how much. An income of £100k a year only gets you around the top 10% of workers.
Needless to say. The closest you get to the center, the more you are competing against the very top percentile, which is filthy rich.
In short, the highest density cannot be as cheap as the mid density because the rent you need to justify that level of building must be higher than the middle levels.
On the other hand, 5 floors is much larger than most areas have. There is plenty of room to grow denser without crossing that limit.
There are also sticky factors. It costs a lot of money to build something. If you already have a building your rent needs to be high to justify tearing down a perfectly good building and building larger. It is possible for rent to be increasing fast in a neighborhood with only a few more people who want to live there than there are units. So you risk building bigger only to discover you can't rent all your new apartments and rent drops for everybody as supply now exceeds demand.
If a large apartment building was built in 1979 with a target rent price of $500/mo, that would have been considered a high-end development. Today, that building could (not necessarily will) provide low-income housing. As it would be paid off and $500/mo per unit could probably still provide enough money for maintenance and upkeep.