Many professional wrestlers need to work really hard in the ring and outside the ring to stay relevant in the eyes of fans. Most fans want pure entertainment. If they don’t get entertained by one particular wrestler, they simply move on to the next.
Wrestlers need to keep evolving their characters and they sometimes fail spectacularly during the process. The Undertaker has managed to somehow keep his gimmick fresh and people still love him. He can hardly perform the moves that he used to perform when he was younger but still manages to entertain the fans both inside and outside the ring.
Some people call The Undertaker the best wrestler of all time. He also has a lot of influence backstage. Taker once used the “American Bad Ass” gimmick and was able to captivate the fans with it. On The Broken Skulls Sessions, The Undertaker spoke about it.
He stated that his previous character was becoming stale. "I always felt like, if I started feeling stale, my audience is probably feeling it before me," Undertaker said. "You get wrapped up in what you're doing.
So, the small changes, the breaks at the right time—but I don't think I would had made it through if I hadn't changed when I did to go to the American Badass. The character—I don't think—would have lasted through the Attitude Era."