If endowments go, so do good professors. My wife was recruited by a couple institutions last year. One of our key concerns about one institution was the endowment. Tenure is not nearly as valuable at a institution that is not on strong financial footing.
Why are endowments so important for Professors? They're not seeing a dime from that anyway.
If a university has a strong endowment, it provides assurance that the operating budget will be buffered against economic downturns. If universities did away with endowments (and did not replace them with mind-boggling amounts of insurance), it would increase the chance that professors' jobs and/or salaries would be at risk. Unlike most jobs, academic positions can last for half a century, so it is reasonable to look far into the future when assessing the desirability of a particular position.
Theoretically, endowments are _supposed_ to be paying for students’ education.