Game companies as a whole are divided into large sections with general foci, and within those sections are subsections of teams with specific foci. Small gears turn the large gears which makes the machine run. The teams responsible for content (IE personal housing) specialize in such, and do not handle debugging, balancing, etc.

Now, content comes off an assembly called a pipeline. This means that stuff like personal housing was in the works many months in advance. In fact, it may surprise you that many MMO comapnies have 2-5 years of content planned out at any given moment. Broken mechanics, bugs, imbalances are unplanned problems that crop up last minute. These not only require immediate addressing, but time to figure out what's causing them. The content department doesn't put their pipeline on hold for the other departments, and vice versa.

This is why content comes regardless of problems the game may be experiencing.