Its very rare that a Heavyweight beats a 'great' in their prime

[Trainer Monkey]

What a difference a year makes, or so the saying goes

Na, its all about getting the beating of your life and never really recovering from it.

Just ask Iron Mike

Which is of course why Frazier wiped out former titlest Jimmy Ellis and perenial contender Jerry Quarry in his next two fights after Ali/Frazier 2
He was only 32 when he packed it in,these days that would be a spring chicken