Or the sponsors they can/want to get don't want to pay the money to end up on whatever channel they are on.
ROH for example have a couple of regular sponsors or hilarious variety (Super beta prostate, a leg brace through a medicare program and a phone dating line) which give them a fair deal of money (and we get wrestlers cutting hammy promos about prostate exams) in return. But they are on free TV channels so I'd assume the ad renting price is cheaper than on channels that cost more to get.
ROH for example have a couple of regular sponsors or hilarious variety (Super beta prostate, a leg brace through a medicare program and a phone dating line) which give them a fair deal of money (and we get wrestlers cutting hammy promos about prostate exams) in return. But they are on free TV channels so I'd assume the ad renting price is cheaper than on channels that cost more to get.