In the absence of other influences, people tend to build with whatever is both cheaper [to buy and to use] and most-available. If clay bricks are plentiful and

In the absence of other influences, people tend to build with whatever is both cheaper [to buy and to use] and most-available. If clay bricks are plentiful and cheaper in an area, then clay bricks tend to be used. If dimensional lumber is plentiful and cheaper, then dimensional lumber tends to be used. Same with concrete, or steel, or whatever. It varies regionally because the availability and cost of resources also vary regionally.