It is actually nearly impossible to find time to actually take a vacation. I had more than 6 months banked when I quit.
Edit. To add to your edit, tenure is far less secure that it appears from outside. It allows you to get away with being a moderate pain, but if you get too bad what they do is make your position redundant in the next departmental reshuffle. Since these occur about every 2 to 3 years tenure is more illusory than real.
You not only have to worry about your position being made redundant, but your whole department. It is easier for admin to get rid of a few troublemakers by killing the whole department than just going after the troublemakers directly. A fair amount of my admin/politics time was spent defending the entire department rather than worrying about my own position directly.