They didn't like the sight of the power lines and put pressure on the Carr Government to get rid of them because they wrecked the views and vistas across the city from the site.
Whether or not it was NBC's that triggered the change, we know for sure they came down. If you are ever at Rockfeller Centre, New York where NBC is based, don't forget to say "Thank you" to them. Trust me the area looks great without them and speaking up did us a favour.
Source: English, B. 1995. "Olympic Eyesore." The Daily Telegraph Mirror, August 30, 4.