Probably because it took him half a life time to figure out wtf had actually happened that night!

To be fair, I think he kinda shadowed Ali over the next few fights... Ali be at Lyle in '75 so Foreman fought and beat Lyle in '75.... Ali beat Fraizer in '75, again Foreman fought and beat Fraizer in '76... Then Ali 'beat' Young in '76 but then Foreman lost to Young, had a breakdown immediately after and retired.

I think he suffered a DEEP mindfuck.