High habitable Real Estate Star Systems

Anyone ever notice that the Rim systems tend to be high habitable real estate star systems?<br /><br />Well at least the home systems for the Rim races are.<br /><br />Look at Osak! 5 inhabited worlds and many of those have moons being used for various purposes<br /><br />Capella and Fochrik have 3 inhabited world each.<br /><br />Just how much inhabitable real estate can we have in star system without stretching believability to D&amp;D fantasy levels?<br /><br />Is the Osak system even possible or do we have to specify that some of those are inhabited by dint of domes and sealed habitat.<br />