Not cable, but broadcasters. They are losing money. Ad revenue has been steadily declining over the last few years. I work in the industry.
Sure ad revenue is declining, that is because there are more options for entertainment than ever before. That is exactly why they are so desperate to get the kickbacks in fees from cable companies.
What cable kicks back to them for everyone who has the channel (including those who never watch it) is much more than a modern distribution platform like Netflix or Amazon would pay for the same content. They are trying to maximize revenue, which is the opposite from what you are claiming.
Their biggest threat was never Aereo or any new distribution platform itself because they can always shut that down. The real threat is a new generation that is more likely to watch random short homemade Youtube videos in their free time than consume traditional episodic television.
The traditional companies are going to milk the shit out of the older generations while they still can and then basically they will die (or at least their current form will die).