Here is a great example to the contrary:
"How do you retain startup employees long after an acquisition? Rackspace acquired Webmail.us in 2007, and today an astounding nine out of the ten original employees including the founders are still at the company and going strong. Can you believe that?" - Bill Boebel, Rackspace VP-Strategy
http://panelpicker.sxsw.com/ideas/view/6405?return=/ideas/in...: