That's precisely it - and they had "Jeb vs. Hillary" bought and paid for. Trump is a wild card - they might be able to buy him off, too, but they aren't sure. And uncertainty is the one thing their business models can't tolerate.
Trump appears that he can be negotiated with, on the basis of whatever he can see clear to calling the greatness of America — but not forced. And these narrow interests cannot, by definition, think outside of their own little distorted boxes. So they would have precious little, if any, negotiation power.