Is it efficient to give a life tenure to university professors?

In France this cultural trait is not a matter of efficiency but a link between official science and the state.

http://www.forbes.com/sites/davidkroll/2013/01/05/top-10-reasons-being-a-university-professor-is-a-stressful-job/

http://www.howtobecomeaprofessor.com/interviews/how-it-feels-not-to-get-tenure/