This excerpt taken from the SIRI 10-Q filed Nov 12, 2008.
Rapid technological and industry changes could make XMs service obsolete.
The audio entertainment industry is characterized by rapid technological change, frequent new product innovations, changes in customer requirements and expectations, and evolving industry standards. If XM is unable to keep pace with these changes, its business may be unsuccessful. Because XM has depended on third parties to develop technologies used in key elements of the XM system, more advanced technologies that it may wish to use may not be available to it on reasonable terms or in a timely manner. Further, XMs competitors may have access to technologies not available to XM, which may enable them to produce entertainment products of greater interest to consumers, or at a more competitive cost.