It seems Ballmer is making a lot former Microsoft employees his enemies. Although I'm not sure I agree with Kempin's asssessment that Microsoft wasn't successful in the tablet market because it didn't follow through on it's ideas:
In his book, Kempin writes about how Microsoft foresaw the major moves in technology in the last decade, but bungled its entry into tablets, phones and social media, ceding leadership in the technology world to Apple Inc and others.
"They missed all the opportunities they were talking about when I was still in the company. Tablets, phones...we had a tablet going, we had tablet software when Windows XP came out, it was never followed up properly," said Kempin.
Microsoft's ideas for phones and tablets were shit, following through on a shit idea isn't going to make it work.