He did. Duval had a bunch of problems and vertigo was surely part of the fall, but his decline started before the vertigo. He freely admits that he lost the motivation needed to stay at that level. He worked his ass off, chased the dream, got to the very top and thought "is this all there is?" Once he got there he found out that being #1 was not as fulfilling as he hoped and he started to slide because he just didn't care. And he had back and wrist and shoulder problems and he really fell off quickly because he was in pain and wasn't motivated to practice, so he just half-assed it. Then he got the vertigo and the bottom fell out.
Non-golfers can't understand how hard golf is on the body, especially to play at that level. It takes a lot of reps hitting hundreds, even thousands of balls every week and every swing is putting a lot of stress on the back, shoulders, knees, elbows and wrists. Every golfer is living on borrowed time, a few freaks can keep going well into their 50s and even into the 60s, but those guys are one in a thousand. Most of them hit a wall physically when they're in the area of 40 years old and a whole lot hit a different wall mentally when they develop the yips later in their careers. Tiger seems to have hit both walls simultaneously. He practiced like a maniac, damaged his body, went to roids and HGH to maintain and get over the injuries, now he's paying the price and as his body went to shit he lost his confidence and now he's a mental basket case too. Getting the chipping yips is nothing physical, it's a simple, effortless motion that puts no stress on the body. He's not struggling in the short game because of his back or his knee or any other physical ailments. It's entirely mental, his brain is mush and he stands over the ball thinking of how he's going to screw up. It happened to Palmer and Hogan and Tom Watson and a lot of other great players. One day you think you can't ever lose and the next you're standing over a short putt or chip and you literally can't swing because you're afraid of what will happen.