Denser cities make it easier to leave them for a short stint, too, because there's less sprawl.

Yes, it's probably a good idea to live outside a city for a while in your life. Though that's up to individual preferences.

I'm not quite sure whether it makes much sense one way or another to say that the US is 'still not very dense'.

In some literal sense, that is obviously true. In another sense, just because eg Russia has huge empty lands in Siberia bringing down the average density on a federal level, doesn't really make a difference to someone living in the suburbs of Moscow.

Similarly, if Russia lost Siberia tomorrow, the person in the Moscow suburb wouldn't experience density any different either.

I only chose Russia as an extreme case example. You can replace Siberia with Alaska or the flyover states, and Moscow and its suburbs with eg San Francisco and Silicon Valley.

After spending years in quite a few different places around the globe, I'm quite happy to live in Singapore these days, one of the premier global cities.

In the US it is sad that because of building restrictions so many people are excluded from its most productive cities; unnecessarily setting back the economy and thus the prosperity of the people. Including even of those people who wouldn't want to live in those most productive places.

This will be my koan for the day.