a. He truly believes he can still win
b. He has an enormous amount of personal pride
c. It’s all about breaking Sam Snead’s record of Tour wins and/or surpassing Jack Nicklaus current record of 17 majors (achievement driven)
Nicklaus has 18 majors.
At this stage, Tiger is largely a ceremonial presence for golf versus a true threat at the majors. There are much better and younger players even if he was 100% (let alone with all of his injuries over time). It’s the same kind of thing that Nicklaus, Palmer, and others went through in their late 40s and 50s. You enjoy watching the legend but you know it’s largely about what once was.