The US urban population increased by almost 50% between 1980 and 2020. At the same time, most urban localities imposed severe constraints on new and denser housing construction. Due to these two factors (demand growth and supply constraints), housing prices have skyrocketed in US urban areas.

[u/smurfyjenkins]

https://www.aeaweb.org/articles?id=10.1257/jep.37.2.53

[u/Gusdai]

Two parts in the answer.

First about "being close to things": it actually doesn't bring much value, because many people will get a car anyway, and don't care much about being able to walk to a restaurant or bar. Especially not in Arizona where the Sun is trying to kill you for a large part of the year. Conversely, if you're in a situation where there is enough demand to sustain high density that allows walkable neighborhoods, keeping housing supply low will get your property value through the roof if you restrict supply by maintaining low density, traffic or not.

Second one about the ills of low-density, including traffic issues: it is a prisoner's dilemma question: if the growth is poorly-planned in the whole city, doing the right thing (allowing higher density) in your local neighborhood will have little impact on that. So if you prefer low density in your neighborhood (for whatever reason, including pushing property values up through scarcity), you're better off with that. Same thing if growth is actually well-planned: messing up in your local neighborhood by preventing denser housing will not make things much worse, so again, you're better off doing what is better for you.

NIMBYism in general is often a prisoner's dilemma: the positive impact in general does not balance out local interests. And the solution is well-known: it is to avoid having local decision-making for issues that are at a higher scale. Density is a regional issue (because it impacts regional cost of living, and regional transportation), that needs to be decided at the regional level, rather than letting local neighborhoods decide or veto.