What's the value of the humanities for society?
The big philosophical concepts, such as knowledge, reason, truth, the mind, freedom, justice, and so on, are inherent to the way we see ourselves, the way we see the world, and our place in it.
These concepts are the structures, the mental scaffolding, that justify how we act and how we think others should act. These are the lenses through which we justify or condemn actions (ours or our opponents'), all with a clean conscience.
Stepping back, introspecting, and reflecting on what we believe in and why we've come to believe it, is thus central to the human pursuit. Having clearly investigated beliefs supports the effort of making sure our actions actually mirror our professed beliefs.
No less importantly, it helps ensure the long-term effects of our material decisions do in fact support building toward what we hold as justified goals.
Liberal arts in general, and History in particular, rather than telling us what we should believe in, go through a historically informed tour of what has been believed in the past and what were the long-term societal consequences of these various pursuits.
What History has shown is that, in many regards, popular action is the product of a short-term reaction to some (perceived or actual) long-term repression. The result of such popular action, though, is well-documented to have mixed results.
It is more common than not for the incoming regime, riding on the back of inflammatory anti-establishment rhetoric and populist legitimacy, to, once in power, use the exact same levers of suppression as the previous regime, by structural necessity.
Any successful government--successful in both multiplying and distributing wealth throughout society--has not been the outcome of any singular virtuous leader who made all the right choices and could govern unrestrained, as intuition would maybe tempt us to believe.
On the contrary, history shows, time and time again, that governments that succeed at producing wealthy, healthy, flourishing societies are the direct product of a designed structure of checks and balances against any single individual's self-interested notions.
By splitting power and creating the necessity of multilateral compromise, it ensures, by design, that legitimacy comes through, not by force, but through cooperation that arises from the weighted competition of plural interests legitimately represented.