When someone leaves a position like this, and then attempts to re-enter the workforce a few years later, are they able to do so at around their old salary? Or have they lost the bargaining chip and must restart substantially lower?
Microsoft needs great people. He will just have more experience in new and unique ways, so he will be more employable.
For Microsoft employees who hit a level and can't get higher, they can probably go to a startup for 2 years and come back at a higher level at Microsoft.