TLDR cost. Wood framing is cheaper and can be made reasonably safe (against fire and earthquakes). Big body buildings fit the most units on a lot. Codes have be

TLDR cost. Wood framing is cheaper and can be made reasonably safe (against fire and earthquakes). Big body buildings fit the most units on a lot. Codes have been getting updates to support this type of construction. Street level retail and/or underground parking and several floors of apartments above are a popular configuration. Concrete can be used on the “podium” (underground and street level) with wood above.