Tiger Woods, with his playoff victory over Rocco Mediate at the 2008 U.S. Open, won his 14th major, and breaking Jack Nicklaus' record of 18 major titles seemed certain. Three years later, this is no longer the case.
History shows that many of the greats lose their winning ways suddenly. Ben Hogan, Arnold Palmer and Tom Watson all suddenly stopped winning majors after dominant periods. Nick Faldo and Seve Ballesteros also saw a sudden drop-off in their games after very solid stretches.
There are many factors that will determine the future of Tiger Woods. However, it is not uncommon to see a golfer stop winning majors while in his prime years.