You can point back to the 2004 benefits overhaul [0], the famous Towels story [1], low compensation rates compared to Google, Amazon and Facebook [2]. Just go over minimsft.blogspot.com posts at the time.

Add to this the lack of vision and direction, catastrophic acquisitions, dismal flagship product releases. At the time there were running jokes about the Inbox filling up with "After 15 years, is time to send that email" subject lines...

  [0] http://old.seattletimes.com/html/businesstechnology/2001938654_microsoft26.html  
  [1] http://www.zdnet.com/article/microsoft-brings-back-the-towels-5000148135/  
  [2] http://minimsft.blogspot.com/2006/03/internal-microsoft-compensation.html