WinXP.Two variants needed?

WinXP seems to be debuting in two flavours HOME and Professional marketed for home users and Work users alike.But since even today many people use Win2000 for home or non-work purposes due to increased security,stability and greater performance.Is it really necessary for Microsoft to launch HOME and PROFESSIONAL variants separately?Shouldn’t they just launch a single OS with configurable options for HOME and WORKSTATION use vis-a-vis SUSE and REDHAT Linux?kindly scope into the logic of strategy of Microsoft behind their WinXP launch.