Ballmer's concept of business is stuck in the Windows XP days, when competitors feared Microsoft's entry into a market. Back in those days, Microsoft could get away with releasing half-baked products, and competitors would run off, knowing that MS's resources would demolish them. Microsoft's mindset was to prevent competitors from entering markets.
The problem now is that it's not 2001 and Microsoft is no longer in a monopoly position. Instead of leveraging their Office and OS market share, they have to enter new markets and win new customers. And they're really struggling at doing this. To win from the ground up Microsoft products would need to have compelling advantage over their competitors, whether it be price, features, or relationship with customers.
How Microsoft went about Windows Phone 7 is an example of their old, "monopoly" playbook failing to work in a new market. Microsoft saw that a market existed, and went to enter the market using the old approach: build a 'good enough' product and hope that competitors give up in fear. The results (which Microsoft refuse to publish out of embarrassment) speak for themselves. Microsoft didn't compete on price - their phones were at mid-level prices, their features were lacking compared to the competition, and any relationship with customers (e.g. enterprise customers using Exchange and Active Directory, etc) failed to materialise because MS didn't implement critical security 'lock down' features on the phone. Microsoft technical staff have the know-how to do these things - but they just don't seem to happen. Is it the management structures? the reward mechanisms? or the corporate strategy? internal politics?
In short, Microsoft is failing at a strategic level. No-one is excited about Microsoft products anymore. No-one thinks their products will be better value or cheaper than the competitors. No-one feels that Microsoft is listening especially closely to anyone except themselves. Microsoft's actions are decidedly tactical, rather than strategic: a new user interface here, some more features there. But without a strategic - CEO - level change, I can't see their situation improving. Having diversified so much, Microsoft will not collapse overnight, but it will continue to slide into irrelevance.