One guy wrote an article about disc brake fade on a descent last winter. He basically used rotors that were too small, the wrong pads, and dragged on the brakes on a descent.

While some people ragged on him for poor technique, his point was much more nuanced. To wit: The road bike market is hyper-focused on weight, and many manufacturers were (are) having a tough time cutting weight without compromising safety. It's also very possible that some subgenius will mix and match rotors and pads, either by accident or with the intent of cutting weight, and that could result in brake fade.

As long as you're using the proper components, pads and technique, you should be just fine with disc brakes on a descent.