[jandrewrogers]

Two reasons: cost and earthquakes.

The US has vast timber forests, so it is inexpensive, and timber (or steel) framing works well for earthquake resistant construction. A large part of the US is a seismic hazard zone and the building regulations reflect that. You can find older neighborhoods with unreinforced masonry throughout the US but those date from a time before they had modern building regulations and before the extent of earthquake risks were fully understood.