If you come from the position that the function of a university is to produce people ready to make difficult things happen, then an answer to this question is very fast to imply itself. Theory is useful in so far as it produces usefulness, and above that it is either contingency planning or wasteful.
There's nothing wrong with having a clear telos. But, as Zizek is wont to point out - if the purpose of education is to produce people ready to solve predefined problems, then that is the death of both ideology and theory. If the overarching goal is usefulness, then the subtler points of reflection and perspective can be sacrificed without any loss. We know what to do, the only thing standing in our way is the lack of manpower to make it happen.
This might have been true if the world was threatened by something undeniably acute, like a huge asteroid approaching the Earth at terminal velocity. When survival hinges on one single factor, then focusing all attention to that one thing is a useful thing to do. There's really no need for theory - just look at the size of that thing! Now go help build the large ass gun that's going to save us all.
Spoiler alert: there's no huge asteroid approaching the Earth at terminal velocity.
Likewise, if the world is going to end, it's probably not going to be because of one single thing. It would rather happen because of the unexpected intermingling of a number of factors. Some of them obvious, some of them not. Most of them needing applied theory in order to be made sense of.
The thing about theory in the absence of huge asteroids is that one never really can tell if it's going to be useful or not. There's no if-then statements that can be made, other than the one that sounds the most useless of them all:
Given enough theory, people will act differently than they would have otherwise.
This goes for all kinds of theory. Rhetoric, comparative literature, political science, philosophy, sociology - the whole gamut of things one can know that are not directly tied to making something happen. You can learn it without at the same time learning to do any one thing in particular, and thus being disqualified from learning anything "useful" - yet you will also see the world in a new way, and approach it in new ways.
Is that useful?
You can paint yourself into all kinds of corners trying to make use out of sense. With enough theory, you will eventually tear down the fourth wall and realize that there is no asteroid, and that you therefore are free to do pretty much whatever you want without it having to be useful. That the world is larger than the scope of one singular task, and that the usefulness of a life is - as of yet - still to be determined.