Why some places are more expensive than others to live in
 

It all boils down to real estate prices, with the USA's fantastic districution systems, power grid, etc. Some places are more expensive than others BECAUSE THEY'RE NICER PLACES TO LIVE. Hence the West Coast is one of the expensive areas. And Dallas is cheap. Law of supply and demand.

It's more complicated than that.

For example, the ability of a metro area to expand and remove the pressure.

Of course it's supply and demand. But you're oversimplifying the lack of supply. Most of the cities with the highest real estate prices are out of room to expand, either because they are hemmed in by geography (Seattle, NYC, San Francisco) or they have alredy had so much growth that the buildable land is too far away (L.A.)

Places like Dallas are cheap because there is so much supply via new building.

Wonderful stuff like mountains, sea coast and rivers tend to complicate growth, yes.

I'll take your mountains, sea coast and river, and raise you 345 days of sunshine.

I already did. It's called the Bay Area.