For me, she started to decline with American Life. But, she recovered With Confessions On A Dancefloor in 2005. I never saw a problem with her Hard Candy era, but I see that she started acting weird on Instagram and social media in the early 10's. I hate to admit it, but it played a part, in her now current embarrassing public image. The last nail in the coffin, for me, was her Rebel Heart era. Always late, and her acting so crazy, she lost me during her Rebel Heart era.
If I were her, and I'm not, I would probably just take some time off and enjoy my throne as the Queen of Pop. Sorry, but a 14 year old girl isn't going to relate to a 63 year old woman. It's not ageism as much as it's a rebellion against one's parents and kids doing their own thing,