This is hugely tangental, but my one time desire to be a humanities scholar (now dead, potential employers you need not worry) always attracts me to article such as this one, about the general screwiness of the university labor system.
...at what point? Most scholars in their sixties are not producing path-breaking new research, but they are precisely the people that tenure protects. Scholars in their twenties and thirties, on the other hand, have no academic freedom at all. Indeed, because tenure raises the stakes so high, the vetting of future employees is much more careful--and the candidates, who know this, are almost certainly more careful than they would be if they were on more ordinary employment contracts. As a result, the process of getting a degree, getting a job, and getting tenure has stretched out to cover one's whole youth. So tenure makes young scholars--the kind most likely to attack a dominant paradigm--probably more careful than they would be under more normal employment process.
I won't make too many comments here, but I wanted to add as a quirky side-note, that I've long been fairly convinced that the screwy job market in academia is partially responsible for the continuing popularity of Karl Marx. An old professor of mine unknowingly drew this line for me, when she said in a lecture that her pre-tenure anxiety over job security was the product of the pressures of the capitalistic system.
Even if your using Marx for non-economic stuff (which is all he's really used for now), his writings are all constrained by the way he imagined a labor market as relatively stagnant. His arguments about people being molded to fit their jobs doesn't really match up with the reality in more dynamic economies, like in China or the Silicon Valley (where I grew up), where people can reinvent themselves every 6 months to fit the needs of a developing market. It does match perfectly job markets where you are trying to get a set job within an entrenched system that rarely changes - such as academia.... or France.