How come Mayweather never fought Kostya Tsysu

[THE THIRD MAN]

It was going to happen if KT got past Hatton, I think at 36 yrs Mayweather would have won.
However, the Tszyu of 1999-2001 is a different story and i think he would have nailed Mayweather at some point, Mayweather was tailor made for him.
It would have taken all of Floyd's defensive skills to avoid getting knocked out, in doing that would he have done enough to win a decision?
I notice that Mayweather never disses Tszyu at this time, afraid of the repercussions Floyd?