> The global average doesn't really mean anything except "somewhere in the US there is still affordable housing".

Friend, that's not what average means.

It means that more than half all houses cost less than X (because average => median). Not "somewhere in the there exists something less than X".

> "high-density places where housing would be needed."

Well you got half the country (actually much more - closer to 2/3, given that average >> median in housing).

This has been brought to you by your local RUMIA (Responsible Use of Math In Arguments) league.

Stay frosty out there, people.