If Mike Tyson, Floyd and Oscar were all on the same card

If Tyson was around today he would be selling 4 million ppv per fight.

 

Given he drew 1.6m not that long ago in the Jones exhibition you might well be right.

 

It just wouldn't make financial sense to have all 3 fighters on the same card.

But to answer your question, the main event would undoubtedly be Mike Tyson.

 

If you look at the history of the ppv records https://en.wikipedia.org/wiki/Pay-per-view#Boxing Tyson fights were all generating the same revenue as mega fights or breaking ppv records. Stands to reason that with the same Hype he had back then now he could do Mayweather / pac, Mayweather / mcgregor numbers regularly and even more.