Although it wouldn't be my dream situation, I babysat for a family in grad school that had a 2BR townhouse. Mom, Dad and baby co-slept in the queen size bed and a two-year old slept in a toddler bed at the foot of their bed. They used the 2nd BR as an office since both parents worked from home.
In other words, different strokes for different folks. Thoughout the world (and in Manhattan!) people keep infants in their room for much longer due to space limitations.