Subsidies for suburbs go deeper. Spread out houses means longer water pipes, electric lines, transformers, etc., paid and maintained by local governments. You might pay more taxes for owning more land, but nowhere near as much as what you owe your community.

More details here :

Suburbia is Subsidized: Here's the Math [ST07]

https://www.youtube.com/watch?v=7Nw6qyyrTeI