Mass Effect 2 launching with DLC?

According to Norweigan paper DagBlaget reports that BioWare, the developers of Mass Effect 2, will be releasing DLC on launch day or shortly thereafter.  This DLC is rumored to include armor, weapons, a new planet and a new ally. 

Gamers such as myself don't hold complaints to DLC but I feel like if DLC is being released that close to the launch date, why wasn't it included in the games original purchase price? 

BioWare has said they are taking DLC very seriously with ME2 and worked in plans to offer DLC during the development process, allowing them to release new content regularly.