The Sightline study linked in the story has a succinct rundown of the situation: http://www.sightline.org/2016/09/06/how-seattle-killed-micro-housing/
"Seattle was the modern birthplace of micro-housing in North America. It went strong from 2009 to 2013, but building micro-housing projects has since become an uphill battle. In fact, the local war about micro-housing is over… and micro-housing lost."