Why did the Holmes-Foreman fight never come off?

I think it was a case that their paths never quite crossed with Foreman's premature retirement. It's a massive loss to boxing this didn't happen between 77-80, even in the 90s it'd be great. I think Holmes always beats Foreman too

 

Their paths didn't cross post-retirement because Foreman didn't want them to. Holmes always wanted that fight and he was bitter about Foreman long after they both retired. Even now he goes on about how Foreman just "found an acorn" with Moorer and he really wasn't that great and etc. I think Holmes would've taken a decision on him any time they would've reasonably fought and that Foreman drew the same conclusion.