Just listening to how the audience is in a frenzy just let's you know that the pandemonium around MJ didn't just start with 'Thriller'. He's been a huge star since childhood. 'Thriller' just catapulted him to another stratosphere.
maybe Mike was pressured and had to be careful what to say because during this period his father Joseph said that he could make solo albums on his own but the condition was that he had to perform live with his brothers because Joseph wanted to keep the family bond. Michael was also uneasy and scared of him ever since he was little as he and his brothers had been abused by him and they all still lived in the same home so by this he was trapped. Then in 84 at the end of the victory tour mike broke it to everyone onstage that it was the last time that he was performing with the rest of the Jackson brothers which got Joseph really pissed. Joseph really couldn’t do anything from then onwards coz Michael’s success was through the roof. I’d say that mike always had ambition to tour alone but he was held back by his father until it was the thriller era