It seems odd to state that Michelangelo is declining, since it is relative to the ascent of Caravaggio, at least according to this article in the NYTmes.com. It’s also not true that Caravaggio has suddenly come out of nowhere. But it is interesting to see how a certain fatigue has likely set in when it comes to Michelangelo and how likely it is that Caravaggio is the beneficiary of that.
I have always thought it fascinating how the reputation and interest in artists waxes and wanes over time. This is an opportunity to see one develop.
(A photo of one of Caravaggio’s works from Virginia Della Rosa’s photostream on flickr.com)
Smart People I Know 
Interesting article, Bernie. I think another factor in this is that over time we seem to become fascinated with different periods of movements (e.g., whether the Roman republic or empire is in vogue). Caravaggio is more representative of early Renaissance (of the North) vs the high Renaissance in Rome. I wonder if one of those shifts is happening now.
It could be. It could also be that Michelangelo was focused on alot during the time of the restoration of the Sistine Chapel, but having that done, people have decided to look to other artists.