The Seattle Times: Business & Technology: Microsoft's busy multitasking

In the Zune context: 

Microsoft would have started its work on Zune a year ago if it could have, showing that even with 71,553 employees, there are limits to the number of new areas it can enter at once.

"Frankly, we took some of the top folks out of the Xbox 360 effort, and right after 360 shipped that became the Zune team," Ballmer said. "I wish we would have done it earlier. We just didn't have the right talent capacity at the time."

Source: The Seattle Times: Business & Technology: Microsoft's busy multitasking