Shareholders and long term investors (aka those who care most about management) look for long term stable growth in core businesses. Yes, you can argue that their performance compared to competitors has been dismal but MSFT is still a solid investment and has seen double digit growth rates for over 10 years - this is incredibly hard for a company this size. Most will argue that this good management.
For example, look at their revenue growth quarter-over-quarter:
http://ycharts.com/companies/MSFT/revenue_growth#series=type...
Also, GOOG and AAPL don't pay dividends (yet), which is a very good proxy for shareholder value:
http://ycharts.com/companies/MSFT/dividend_yield#series=type...
I'm not saying MSFT can't do better; OP asked why Ballmer is tolerated and I wanted to point out that there are plenty of reasons why.