Tito has competed straight through at a fairly high level, no huge break from the sport, always in shape as others have mentioned.
Chuck was basically forced into retirement around ten years ago when his chin turned to dust after relying on his ability to take a shot rather than learn and implement proper defensive striking techniques.
Styles:
Tito is a grappler, ground and pound and submissions. As such he spent less time "trading blows" in the pocket and hasn't been KOed (most if not all of his stoppage losses were TKO).
Chuck, though he was a division 1 wrestler, fought exclusively as a striker/kickboxer in his MMA career. His success relied heavily on him being able to withstand the other guys' shots while they could not take his. (Eventually this strategy failed when his chin went.). As such he took several BAD KO LOSSES, not to mention presumably a ton of shots over the years in sparring.
Chuck's style requires reflexes and speed, the first things to go on an aging athlete.
Tito's style relies more on brute strength, technique, power. Things that he still has for the most part.
In their UFC years Tito couldn't take Chuck down and didn't offer him a threat standing.
UUUUGE advantage Chuck.
Tito's striking never evolved into anything beyond somewhat passable rudimentary boxing, but his chin still seems fine.
Chuck had way way better striking but I doubt it will be effective at his current very slow speed and his aparent inability to throw more than 3 punches without taking a break.
This fight, or any fight involving Chuck Liddell in 2018, should not have been sanctioned.
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