Very true. Remember, the first Chael fight followed the Demian Maia debacle. At that point in time, Anderson was not the beloved and universally respected figure he would become. People we legitimately asking that he, the reigning champion, be cut because of the performance. Dana was even promising to somehow make it up to the fans for such a disaster. This seems ridiculous in retrospect. Most of Silva's fights were finishes to that point. However, it's true that he was not a fan favorite/draw at this point in time.
Chael changed all of that. Their feud was legendary. Anderson's comeback win was magical. Chael provided Silva the perfect foil. Chael gave him his villain. Following their first fight, Silva blew up in popularity. The subsequent Vitor kick then accelerated his popularity even more so and the eventual Sonnen rematch was humongous.
Chael did his job perfectly. He helped make the best fighter in the world into the draw he should have been all along. Likewise, the feud gave Chael, to that point an unheralded wrestler with a grinding style, the chance to shine and make a career for himself as well. No two fighters have ever been as mutually beneficial to one another as Silva and Sonnen were.