World enough and time
Among other things, the MLA's recommendations for tenure overhaul warn against “the tyranny of the monograph.” In the SUNY system, it's the rare department outside one of the four research campuses that requires a monograph for tenure; while my department's tenure requirements (five articles) are considered pretty stringent on my campus, we still don't require a monograph. Nevertheless, the profession's increasing emphasis on both quantifiable productivity and a required monograph for tenure--the latter of which Michael Bérubé calls "a recent blip in our history"--does do away with something integral to any large-scale research project: time.
It is very difficult to do good scholarship quickly, especially if the scholarship in question involves any degree of scope. Right now, I'm working on a rather daunting project that requires, among other things, both a fair amount of archival work and considerable reading in a field a few centuries outside my own. (Far be it for me to write anything short...) Even though I'm tenured at a teaching-oriented campus, though, time is still of the essence: I need to publish enough to qualify for merit increases, to remind other people on the planet of my continuing professional existence (especially since I really can't afford to attend more than one or perhaps two conferences per year), and, with any luck, to get promoted again. It's no longer possible, that is, to work for years and years on a Big Project, as an academic in the first 2/3 of the twentieth century might reasonably expect to do; in fact, given the push for post-tenure review, a senior scholar who tries to focus on a Big Project at the expense of "smallest publishable units" might find herself looking uncomfortably like the dreaded deadwood.
I've heard tell of some departments that deliberately restrict the number of publications a candidate for tenure and promotion can submit for consideration. This seems to me to be one way of emphasizing quality over quantity--not to mention reminding us of the value of time.