Universities, and the people within it, often like to project the image of an egalitarian society. "This is your university", "A university is made up of professors", "WE run the place", and so on. Nowadays, in the era of 'university-as-business-enterprise', these buzzphrases are often supplemented by, "we're all partners in this enterprise", and other business metaphors.
There's one obvious way in which this is fiction: the tenured/non-tenured divide is vast, and dominates the thinking of the untenured in many ways. Continuing the business metaphors, the tenured/untenured divide is like the partner-associate divide at law firms or investment banks.
But factoring that out, there are more subtle hierarchies: the administrative pathway (chair to dean to provost) is one obvious one, and there are class hierarchies based on funding output, fame, and other parameters like that.
In itself, this is not particularly noteworthy: where humans exist, hierarchies are sure to follow. What I find interesting to observe is how the lack of an institutionalized hierarchical structure (that we see in a company) removes some of the obvious external cues that help us slot into our various positions in the hierarchies. In other words, you have to be reasonably socially aware to pick up on the signals that indicate hierarchical patterns in academia, and once you do, you have to constantly remind yourself that they exist, otherwise you run the risk of silently crossing lines that you shouldn't be crossing.
The key issue here is that the natural tendency to form hierarchies is in this case going counter to the professed semi-fiction of equality, and it's the conflict between the two views that makes for an interesting social dynamic.
In all the ink that gets spilled about academia vs industry, this is one of the more subtle issues that crops up. I doubt it makes a difference to anyone's decision on which way to go, but it's curious nonetheless.