Although it's a bit patchwork, most spectrum rights (from auction to licensure) are use-it-or-lose-it. On licenses as simple as an FM broadcast license, station

Although it's a bit patchwork, most spectrum rights (from auction to licensure) are use-it-or-lose-it. On licenses as simple as an FM broadcast license, stations must report to the FCC if they will not be broadcasting for any period of time, and if they remain "dark" for too long they face cancellation of their license for non-use. On spectrum auctions it's usually a condition of the license that it will be cancelled if certain conditions specific to the spectrum aren't met, e.g. offering a certain range of services to a certain volume of customers.