The effective owners are the trustees (or the legislature, in the case of state universities), and they want to keep costs down and make sure that labor is docile and obedient. The way to do that is, essentially, temps. Just as the hiring of temps has gone way up in the neoliberal period, you're getting the same phenomenon in the universities. The idea is to divide society into two groups. One group is sometimes called the "plutonomy" (a term used by Citibank when they were advising their investors on where to invest their funds), the top sector of wealth, globally but concentrated mostly in places like the United States. The other group, the rest of the population, is a "precariat," living a precarious existence.