The first time I recall someone speaking truth to power because of conviction was Kai Nagata.
Since then, we've had Greg Smiths, Andrew Coynes and Dan Gardners. They're all still finding success; speaking truth to convention has perhaps redirected their trajectory, but it hasn't killed them. In fact, by stripping away the false pretenses that have probably chafed, their honesty has probably empowered them. The very notion of bluntly, plainly speaking truth to convention has even taken root in popular culture.
Of course, all of this comes with caveats - there's a difference between calling a spade a spade and going on an emotion-fueled rant. One could very well put Rob Ford's "run 'em out of town" comment in this category, where it doesn't belong. There's a big difference between defining authentic problems and finding comprehensive, structural solutions.
Those are only found through conversation, which can only be conducted in an atmosphere of open and mutual respect. In any conversation where are buttons are consciously or unconsciously being pushed, the instinct to react instead of internalize and understand is hard to fight and ever harder to recognize. But that's the challenge we face if we're to get past this period of stagnation and keep moving forward.
This is the challenge of the 21st Century; the realization of a consciously, strategically collaborative society. To bridge this gap takes a different kind of leader than we're used to; rhetoric and positioning aren't enough. What's required today are integrity, honour, and foresight.