Trump tweets his parade for free while the networks are counting on more than a billion dollars of TV ads in 2016 to put them in the black. It worked in 2012 but is now in jeopardy. FOX too has to hate him because he puts a chunk of their business plan in the dumpster. When Trump pulled an end run on the final GOP network debate, he didn't lose. Though he sounds bizarre asking FOX to make a $5,000,000 donation to the vets, this is naughty politics but good business. FOX knows they will make substantially more from the one evening's ad sales. Bring it on, let the networks scramble for a diminishing pile of dollars. That's what social media are for, to bring down the cost of getting in touch.
Hollywood pays the big bucks out for star power. Top pitchers and quarterbacks command stunning sums. Campaigning is no different. The television people ascended to power in the fifties and have had half a century pulling the strings of public news and they pay for ratings. Paying candidates directly to appear on a show sounds iffy to me, but paying a tax to an honourable third party charity to have them on the show sounds just fine. Should they be elected to public office, the rules change for they owe an answer to the voters who put them there.