Stations have lots of expenses beyond what you mention.The Preaching and Teaching signals are pure profit as they charge for airtime! The only cost (is in time) to Salem is loading the files in automation and that can be easily done in a shared production role with one of their conservative talkers.
First, there is tax or rental of the studio and the transmitter site. Utilities for both. Insurance of several kinds. An engineer on staff or on a fee basis. Someone to load the programs on the system. Someone to do required logs, someone to do billing and a manager who sells the time. There is FICA, business licenses, all sorts of state and city permits and fees. Cleaning and maintenance of the offices and transmitter site. Periodic painting of the tower or lease payments for a rented tower. Dues in NAB, the state association and RAB. Trade magazines and newsletters. Internet access, website costs. Software (most broadcast industry programs are on a fee basis, not a buy-out). Repairs and parts for transmitter and studio gear. Computers, printers and related supplies. Commissions for sales persons.
I could go on with what I'm sure are a number of things I have omitted.
Such stations are NOT pure profit. In many cases today, they are very difficult, particularly in smaller and medium markets.