Tenure RIP?

Tenure is an interesting issue in academia most academics think of tenure as the holy grail and that it is not to be touched.  The economics of tenure suggests that it creates poor incentives.  Individuals early on in their career have the incentive to publish and stay quiet while they work to receive tenure. Once one has tenure there is no incentive to publish again, or at least at the same effort without fear of recourse.  I personally worked at university that did not have a formal tenure system, and I never noticed anyone afraid to speak out, or work on the research that they were interested in pursuing.  Two recent articles on tenure that are worth reading.  One is from the Chronicle of Higher Education explaining that tenure track positions are declining.  The other is from the Atlantic describing some of the problems and supposed benefits of tenure.

The question is why is academia so sacred?  Should academics be free to say what ever they want without consequence?  Other fields do not have this benefit.  Now I do understand wanting to maintain academic integrity and scholarship I am just not sure that tenure is necessary to ensure this position.  No university wants the reputation of letting people go for not agreeing with the administration just as businesses would not want the reputation of mistreating their employees.  Is tenure on the way out?  Will it cause academia to crumble?  I doubt it.