Academic Freedom
Academic work is work which is informed by nothing but the object of inquiry.
Basic Concept
All humans need information as a basis for making informed decisions, and thus ultimately to pursue happiness and to lead a good life in general. This information pertains to reality. The objective of academic work is to provide such information, with as little bias as possible.
Academic Freedom
Academic freedom is freedom from any influence (e.g. direction, coercion), so that academic work is only informed by reality. It is thus not a "perk", it is a fundamental necessary prerequisite.
Significance for Society and Economy
Human beings in most social contexts are influenced by man-made constraints, such as competition, being managed or being coerced. All results of activities in such conditions are informed by these influences, up to the point that it may be entirely artificial.
As an extreme example, consider a society driven only by such artificial information generated by itself. This society would lose contact to reality and effectively operate blindly. However, such failure to perceive reality will not change anything about the impact that reality has on this society. Eventually, the real basis sustaining this society would disappear (or perhaps even be destroyed by the actions of the society), with disastrous consequences.
The significance of academic work is to provide objective information. Therefore, sustaining an academic sector is not a luxury, it is a necessity for survival of any society.