This scan from 1978 explains following things :

1. The term superstar used for Rajesh Khanna first.
2. His immediate fall.
3. But in real sense first ever super star was Shammi Kapoor.
4. Amitabh is first superstar whose 6 movies always running simultaneously in one city.
5. They were predicting same fate of Amitabh like Rajesh Khanna, because old superstars like Dev Anand etc always did one movie at one time and have long lasted career. So they were predicting sharp fall of Amitabh very soon because of over exposure.

 

http://bollybusiness.wordpress.com/2012/07/19/filmfare-on-superstar-and-first-real-superstar/