Amitabh was number 1 when Vinod Khanna left for Osho Ashram
and he was Number 1 even when Vinod Khanna made a comeback in 1987.
The ones who actually benefited from Vinod Khanna’s absence were Jeetendra and Mithun. Jeetendra was the number 2 star between 1980–84, Mithun was the number 2 star from 1985–88 and Anil Kapoor was the number two after 1988 till 90. After that it was one or another khan in the top 3.
In 1982 the 4 out of 10 highest-grosser films belonged to Amitabh (Namak Hallal, Khuddar, Shakti, Satte pe Satta), Vinod Khanna had Rajput, which earned 3.75 crores, but it was a multi starrer film and thus remained average. Jeetendra had Farz aur Kanoon which earned 4.5 crores, and Mithun became a breakout star with the global success of Disco Dancer.
1983–84 were the golden years of Jeetendra with his south remake hits like Himmatwala, Justice Chaudhary Mawali, Tohfa, Maqsad etc. Mithun emerged as the top star in 1985 with the blockbuster hit Pyar Jhukta Nahi along with his steady stream of hits. When Vinod Khanna entered the films again he did had hits like Insaaf and Satyamev jayate but after that hee struggled for big hit ts except a heroine centric Chandni. Amitabh had clear dominance till 1988 and even then his flops earned more than the hits of other actors ( a crap like Toofan earned the same as Chandni)