They NEED to do something with the cash reserve because they are a publicly traded company, and investors are greedy. While it would never realistically happen, a coalition of investors could demand cash distributions and threaten to vote out the board if they don't comply.
What kind of psychotic, suicidal investors group would kick out the board that has secured the kinds of returns this board has? I mean, I understand what you're saying but it seems like it would go against common sense to do something like that.
The kind that feels they could put in their own board members and have them immediately distribute Apple's cash hoard to the investors, at which point the investors cut and run. I don't think Apple has so much money that this is a profitable gambit at the moment, but at some bank balance you'd be stupid not to at least contemplate the option (especially since you can't expect the stock value to grow at its current rate indefinitely...).
