For ’tis the sport to have the engineer hoist with his own petard. Donald Trump’s meteoric rise in the GOP nomination fight has come in large part from his skillful use of “earned media” — free coverage, in other words, by media outlets. Trump’s campaign has spent almost no money on advertising, at least so far, in large part because they don’t need to do so. Their candidate gets wall-to-wall coverage thanks to his outrageous statements and larger-than-life persona, while other candidates have to spends tens of millions hoping in vain to keep up.

Now that other candidates (Jeb Bush especially) have packed it up, suddenly media outlets are looking at the cost of giving the milk for free rather than selling the cow. Reuters reported yesterday that “Trump’s low advertising spending weighs on U.S. broadcasters.” No kidding!

Republican frontrunner Donald Trump has upended the presidential primaries this year by relying heavily on free air time and Twitter at the expense of local-ad buying, throwing into question estimates that the November presidential election could translate into $6 billion spent on TV advertising.

Now, with no Trump TV ads scheduled going into the 11-state Super Tuesday primaries, some investors and analysts are growing increasingly concerned that Trump could continue with an advertising-light strategy built on bruising debate performances and large rallies – often shown on cable TV – even if he wins the Republican Party nomination.

“For the broadcast industry, which has pinned its 2016 on local TV ad spend, you have to believe that someone who is pretty amazing at leveraging the power of social media would be a real problem for television,” said media analyst Rich Greenfield with New York-based equity firm BTIG Research. “I think Trump elevates that to a whole new level.”

It’s not that Trump hasn’t spent money at all, but he hasn’t spent much relative to his competition. According to Reuters’ calculations, Trump has spent $10 million, while Bush and his allies spent $85 million and ended up with four whole delegates. Hillary Clinton has spent $32 million, which may be $31 million than she’d figured to spend on primary ads when she started campaigning a year ago. Republicans, however, expected to spend — and broadcasters expected them to do so as well. In fact, they literally banked on it, and now it looks as though the political cycle might bust them.

Marco Rubio appears to have caught on, a little late perhaps. He and his allies have combined for $49 million in ad spends over the course of the campaign, but what boosted his profile most with the media? Attacking Trump as a con man and ridiculing him on the stump. Suddenly Rubio elbowed his way into the TV frame without spending a dime on advertising, and the late-breaking deciders from last night seem to have validated that approach. When challenged by the handwringers of the media who enabled Trump over his change of tone, Rubio has told them that he’s only responding to the market incentives they’ve established. And he’s exactly correct.

Small wonder, then, that those who see the media as a malevolent force love the impact that Trump has had on the industry. He’s managed to get them to eat themselves by pursuing his outsize persona as a ratings draw. Instead of covering the circus, so to speak, they joined the circus — and now they’re paying a big price for it. There is a lesson to be learned from this, but so far, it doesn’t appear that the mainstream media has begun to learn it yet.