His health issues have been in the news lately
His health issues have been in the news for like two decades. There's always another new article on how he has severe health problems and will die anytime soon. He's been terminally ill and dying since the millennium panic
I'm sorry but... Most of them? Especially since it's his performance that has become poor. He is playing himself more and more. A similar thing happened to Johnny Depp. Look at both of them in What's Eating Gilbert Grape and then at stuff like Great Gatsby, Wolf of Wall Street, Shutter's Island, Django / Willy Wonka, Pirates of the Carribean, Shadows, Transcendence. The acting and characters are so similar and they don't give an effort anymore (or try to, and absolutely overdo it).
(Sorry I somehow incorporated a Johnny Depp rant in a critic of DiCaprio, their story of decline is just too similar to me. And Gilbert Grape is an amazing movie.)