And yet NYC and Tokyo are housing way, way more people than San Francisco, so they&#x27;re actually a lot more successful at being a city in comparison.  All of that density has lots of advantages -- and I say that as a Manhattan resident who rarely goes anywhere outside of Citibike range.  I certainly wouldn&#x27;t trade my current situation for the comparative sparseness of San Francisco at the same price.<p>New York City also does still have lots of opportunities to build upwards, many of which are being taken.  A huge amount of housing inventory is coming online each year.  The city is accommodating large influxes of new people.  It could be doing even better with less restrictive air rights, but things could always be improved.  San Francisco isn&#x27;t doing as well by comparison.<p>And keep in mind, it&#x27;s not like there&#x27;s an infinite number of people living on the planet.  Nor does building denser cities cause more people to be born that otherwise would (if anything, it&#x27;s less).  Housing demand thus isn&#x27;t infinite, and it doesn&#x27;t logically follow that addressing housing demand by building lots more housing is a self-perpetuating problem.