This is the one factor driving the rest. There is no shortage of housing. We already have enough physical capacity to house every women, man and child. What we don't have enough of is affordable housing. While everything else you mention is a factor, the "price" of the land itself is the most important one, and the cause of the 2008 depression. Our system not only allows speculation in land prices, it encourages it. But none of us created the land, did we? So how can we claim to own it?
Buying and selling the land itself is specifically prohibited in Leviticus 25:23, and most other major religions as well. If we observed that commandment, we would not have these problems.
In the meantime, there are some other ways to mitigate the problems of land speculation.
